Index: .github/workflows/amiga-gcc.yml
==================================================================
--- .github/workflows/amiga-gcc.yml
+++ .github/workflows/amiga-gcc.yml
@@ -1,10 +1,15 @@
 name: amiga-gcc
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --disable-amiga-lib
     steps:
     - name: Install dependencies
       run: docker pull amigadev/crosstools:m68k-amigaos
     - uses: actions/checkout@v2
     - name: autogen.sh
@@ -13,11 +18,11 @@
       run: |
         docker run \
           -e PATH="/opt/m68k-amigaos/bin:$PATH" \
           -v "$PWD:/objfw" \
           amigadev/crosstools:m68k-amigaos \
-          sh -c 'cd /objfw && ./configure --host=m68k-amigaos'
+          sh -c 'cd /objfw && ./configure --host=m68k-amigaos ${{ matrix.configure_flags }}'
     - name: make
       run: |
         docker run \
           -e PATH="/opt/m68k-amigaos/bin:$PATH" \
           -v "$PWD:/objfw" \

Index: .github/workflows/macos-10.15.yml
==================================================================
--- .github/workflows/macos-10.15.yml
+++ .github/workflows/macos-10.15.yml
@@ -1,19 +1,31 @@
 name: macos-10.15
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: macos-10.15
+    strategy:
+      matrix:
+        configure_flags:
+          - 
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
     steps:
     - name: Install dependencies
       run: brew install autoconf automake
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure
+      run: ./configure ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(sysctl -n hw.logicalcpu)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/macos-11.yml
==================================================================
--- .github/workflows/macos-11.yml
+++ .github/workflows/macos-11.yml
@@ -1,19 +1,31 @@
 name: macos-11
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: macos-11
+    strategy:
+      matrix:
+        configure_flags:
+          - 
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
     steps:
     - name: Install dependencies
       run: brew install autoconf automake
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure
+      run: ./configure ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(sysctl -n hw.logicalcpu)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-18.04-32bit.yml
==================================================================
--- .github/workflows/ubuntu-18.04-32bit.yml
+++ .github/workflows/ubuntu-18.04-32bit.yml
@@ -1,19 +1,35 @@
 name: ubuntu-18.04, 32 bit
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - name: Install dependencies
       run: sudo apt install gcc-multilib
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure OBJC="clang -m32"
+      run: ./configure OBJC="clang -m32" ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-18.04-gcc-32bit.yml
==================================================================
--- .github/workflows/ubuntu-18.04-gcc-32bit.yml
+++ .github/workflows/ubuntu-18.04-gcc-32bit.yml
@@ -1,19 +1,35 @@
 name: ubuntu-18.04, GCC, 32 bit
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - name: Install dependencies
       run: sudo apt install gcc-multilib gobjc
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure OBJC="gcc -m32"
+      run: ./configure OBJC="gcc -m32" ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-18.04-gcc.yml
==================================================================
--- .github/workflows/ubuntu-18.04-gcc.yml
+++ .github/workflows/ubuntu-18.04-gcc.yml
@@ -1,19 +1,35 @@
 name: ubuntu-18.04, GCC
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - name: Install dependencies
       run: sudo apt install gobjc
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure OBJC="gcc"
+      run: ./configure OBJC="gcc" ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-18.04.yml
==================================================================
--- .github/workflows/ubuntu-18.04.yml
+++ .github/workflows/ubuntu-18.04.yml
@@ -1,17 +1,33 @@
 name: ubuntu-18.04
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-18.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure
+      run: ./configure ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-20.04-32bit.yml
==================================================================
--- .github/workflows/ubuntu-20.04-32bit.yml
+++ .github/workflows/ubuntu-20.04-32bit.yml
@@ -1,19 +1,35 @@
 name: ubuntu-20.04, 32 bit
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - name: Install dependencies
       run: sudo apt install gcc-multilib
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure OBJC="clang -m32"
+      run: ./configure OBJC="clang -m32" ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-20.04-gcc-32bit.yml
==================================================================
--- .github/workflows/ubuntu-20.04-gcc-32bit.yml
+++ .github/workflows/ubuntu-20.04-gcc-32bit.yml
@@ -1,19 +1,35 @@
 name: ubuntu-20.04, GCC, 32 bit
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - name: Install dependencies
       run: sudo apt install gcc-multilib gobjc
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure OBJC="gcc -m32"
+      run: ./configure OBJC="gcc -m32" ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-20.04-gcc.yml
==================================================================
--- .github/workflows/ubuntu-20.04-gcc.yml
+++ .github/workflows/ubuntu-20.04-gcc.yml
@@ -1,19 +1,35 @@
 name: ubuntu-20.04, GCC
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - name: Install dependencies
       run: sudo apt install gobjc
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure OBJC="gcc"
+      run: ./configure OBJC="gcc" ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install

Index: .github/workflows/ubuntu-20.04.yml
==================================================================
--- .github/workflows/ubuntu-20.04.yml
+++ .github/workflows/ubuntu-20.04.yml
@@ -1,17 +1,33 @@
 name: ubuntu-20.04
 on: [push, pull_request]
 jobs:
   tests:
     runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        configure_flags:
+          -
+          - --enable-seluid24
+          - --disable-compiler-tls
+          - --disable-threads
+          - --disable-threads --disable-sockets
+          - --disable-threads --disable-files
+          - --disable-threads --disable-sockets --disable-files
+          - --disable-sockets
+          - --disable-sockets --disable-files
+          - --disable-files
+          - --disable-shared
+          - --disable-shared --enable-seluid24
+          - --disable-compiler-tls --disable-threads
     steps:
     - uses: actions/checkout@v2
     - name: autogen.sh
       run: ./autogen.sh
     - name: configure
-      run: ./configure
+      run: ./configure ${{ matrix.configure_flags }}
     - name: make
       run: make -j$(nproc)
     - name: make check
       run: make check
     - name: make install
       run: sudo make install