Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -737,39 +737,10 @@
 ])
 AS_IF([test x"$ac_cv_c_bigendian" = x"universal"], [
 	AC_DEFINE(OF_UNIVERSAL, 1, [Whether we are building a universal binary])
 ])
 
-AC_MSG_CHECKING(for SIZE_MAX)
-AC_EGREP_CPP(egrep_cpp_yes, [
-	#include <stdint.h>
-	#include <limits.h>
-
-	#ifdef SIZE_MAX
-	egrep_cpp_yes
-	#endif
-], [
-	AC_MSG_RESULT(yes)
-], [
-	AC_MSG_RESULT(no)
-	AC_MSG_CHECKING(for SIZE_T_MAX)
-	AC_EGREP_CPP(egrep_cpp_yes, [
-		#include <stdint.h>
-		#include <limits.h>
-
-		#ifdef SIZE_T_MAX
-		egrep_cpp_yes
-		#endif
-	], [
-		AC_MSG_RESULT(yes)
-		size_max="SIZE_T_MAX"
-	], [
-		AC_MSG_RESULT(no)
-		size_max="(~(size_t)0)"
-	])
-	AC_DEFINE_UNQUOTED(SIZE_MAX, $size_max, [Maximum value for size_t])
-])
 AC_MSG_CHECKING(for SSIZE_MAX)
 AC_EGREP_CPP(egrep_cpp_yes, [
 	#include <stdint.h>
 	#include <limits.h>
 
@@ -778,12 +749,11 @@
 	#endif
 ], [
 	AC_MSG_RESULT(yes)
 ], [
 	AC_MSG_RESULT(no)
-	AC_DEFINE(SSIZE_MAX, [((ssize_t)(SIZE_MAX / 2))],
-		[Maximum value for ssize_t])
+	AC_DEFINE(SSIZE_MAX, [(SIZE_MAX / 2)], [Maximum value for ssize_t])
 ])
 AC_MSG_CHECKING(for UINTPTR_MAX)
 AC_EGREP_CPP(egrep_cpp_yes, [
 	#include <stdint.h>
 	#include <limits.h>
@@ -793,11 +763,13 @@
 	#endif
 ], [
 	AC_MSG_RESULT(yes)
 ], [
 	AC_MSG_RESULT(no)
-	AC_DEFINE(UINTPTR_MAX, [(~(uintptr_t)0)], [Maximum value for uintptr_t])
+	AC_CHECK_SIZEOF(uintptr_t)
+	AC_DEFINE(UINTPTR_MAX,
+		[(SIZEOF_UINTPTR_T * CHAR_BIT)], [Maximum value for uintptr_t])
 ])
 
 AC_CHECK_HEADER(inttypes.h,
 	[AC_DEFINE(OF_HAVE_INTTYPES_H, 1, [Whether we have inttypes.h])])
 
@@ -843,41 +815,10 @@
 AC_MSG_RESULT($fp_endianess)
 AS_IF([test x"$fp_endianess" = x"unknown"], [
 	AC_MSG_ERROR(
 		[Floating point implementation does not conform to IEEE 754!])])
 
-AC_MSG_CHECKING(for INFINITY)
-AC_COMPILE_IFELSE([
-	AC_LANG_PROGRAM([
-		#include <stdio.h>
-		#include <math.h>
-	], [
-		printf("%f", INFINITY);
-	])
-], [
-	AC_MSG_RESULT(yes)
-], [
-	AC_MSG_RESULT(no)
-
-	AC_MSG_CHECKING(for __builtin_inf)
-	AC_COMPILE_IFELSE([
-		AC_LANG_PROGRAM([
-			#include <stdio.h>
-		], [
-			printf("%f", __builtin_inf());
-		])
-	], [
-		AC_MSG_RESULT(yes)
-		AC_DEFINE(INFINITY, [(__builtin_inf())],
-			[Workaround for missing INFINITY])
-	], [
-		AC_MSG_RESULT(no)
-
-		AC_MSG_ERROR([Neither INFINITY or __builtin_inf was found!])
-	])
-])
-
 case "$host_cpu" in
 	arm* | earm*)
 		AC_MSG_CHECKING(for VFP2 or above)
 		AC_COMPILE_IFELSE([
 			AC_LANG_PROGRAM([], [

Index: src/OFString+JSONParsing.m
==================================================================
--- src/OFString+JSONParsing.m
+++ src/OFString+JSONParsing.m
@@ -29,10 +29,14 @@
 #import "OFDictionary.h"
 #import "OFNumber.h"
 #import "OFNull.h"
 
 #import "OFInvalidJSONException.h"
+
+#ifndef INFINITY
+# define INFINITY __builtin_inf()
+#endif
 
 int _OFString_JSONParsing_reference;
 
 static id nextObject(const char **pointer, const char *stop, size_t *line,
     size_t depthLimit);

Index: src/OFString.m
==================================================================
--- src/OFString.m
+++ src/OFString.m
@@ -74,10 +74,14 @@
 
 #ifdef OF_AMIGAOS_M68K
 /* libnix has strtod, but not strtof */
 # define strtof strtod
 #endif
+
+#ifndef INFINITY
+# define INFINITY __builtin_inf()
+#endif
 
 static struct {
 	Class isa;
 } placeholder;
 

Index: src/objfw-defs.h.in
==================================================================
--- src/objfw-defs.h.in
+++ src/objfw-defs.h.in
@@ -1,8 +1,5 @@
-#undef INFINITY
-#undef LLONG_MAX
-#undef LLONG_MIN
 #undef OF_APPLE_RUNTIME
 #undef OF_BIG_ENDIAN
 #undef OF_FLOAT_BIG_ENDIAN
 #undef OF_HAVE_ATOMIC_BUILTINS
 #undef OF_HAVE_ATOMIC_OPS
@@ -46,9 +43,5 @@
 #undef OF_NINTENDO_DS
 #undef OF_NO_SHARED
 #undef OF_OBJFW_RUNTIME
 #undef OF_UNIVERSAL
 #undef OF_WII
-#undef SIZE_MAX
-#undef UINTPTR_MAX
-#undef ULLONG_MAX
-#undef __have_longlong64

Index: tests/OFStringTests.m
==================================================================
--- tests/OFStringTests.m
+++ tests/OFStringTests.m
@@ -24,10 +24,14 @@
 #import "TestsAppDelegate.h"
 
 #import "OFString.h"
 #import "OFMutableUTF8String.h"
 #import "OFUTF8String.h"
+
+#ifndef INFINITY
+# define INFINITY __builtin_inf()
+#endif
 
 static OFString *module = nil;
 static OFString *whitespace[] = {
 	@" \r \t\n\t \tasd  \t \t\t\r\n",
 	@" \t\t  \t\t  \t \t"