fi
dnl Compiler flags
-DESIRED_FLAGS="-Wall -W -Wextra -pipe -Wno-long-long -Winline -Wvla -Wno-overlength-strings -Wunsafe-loop-optimizations -Wundef -Wformat=2 -Wlogical-op -Wsign-compare -Wformat-security -Wmissing-include-dirs -Wformat-nonliteral -Wold-style-definition -Wpointer-arith -Winit-self -Wdeclaration-after-statement -Wfloat-equal -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-declarations -Wmissing-noreturn -Wshadow -Wendif-labels -Wcast-align -Wstrict-aliasing=2 -Wwrite-strings -Wno-unused-parameter -ffast-math -Wp,-D_FORTIFY_SOURCE=2 -fno-common -fdiagnostics-show-option"
-
-for flag in $DESIRED_FLAGS ; do
- CC_CHECK_CFLAGS([$flag], [CFLAGS="$CFLAGS $flag"])
-done
+CC_CHECK_CFLAGS_APPEND([-Wall -W -Wextra -pipe -Wno-long-long -Winline -Wvla -Wno-overlength-strings -Wunsafe-loop-optimizations -Wundef -Wformat=2 -Wlogical-op -Wsign-compare -Wformat-security -Wmissing-include-dirs -Wformat-nonliteral -Wold-style-definition -Wpointer-arith -Winit-self -Wdeclaration-after-statement -Wfloat-equal -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-declarations -Wmissing-noreturn -Wshadow -Wendif-labels -Wcast-align -Wstrict-aliasing=2 -Wwrite-strings -Wno-unused-parameter -ffast-math -Wp,-D_FORTIFY_SOURCE=2 -fno-common -fdiagnostics-show-option])
dnl Linker flags.
dnl Check whether the linker supports the -version-script option.
[VERSIONING_LDFLAGS='-Wl,-version-script=$(srcdir)/map-file'])
AC_SUBST([VERSIONING_LDFLAGS])
+dnl Check for the proper way to build libraries that have no undefined
+dnl symbols; on some hosts this needs to be avoided but the macro
+dnl takes care of it.
+CC_NOUNDEFINED
+
dnl Check whether to build tests by default (as compile-test) or not
AC_ARG_ENABLE([default-build-tests],
AS_HELP_STRING([--disable-default-build-tests], [Build test programs only during make check]))
[LIBLTDL=])
AS_IF([test "x$LIBLTDL" = "x"],
- [AC_MSG_ERROR([Unable to find libltdl.])])
+ [AC_MSG_ERROR([Unable to find libltdl version 2. Makes sure you have libtool 2.2 or later installed.])])
AC_SUBST([LIBLTDL])
#### Determine build environment ####