Fix for hardcoding CFLAGS and broken test for mkdir
https://bugs.gentoo.org/898992
--- a/configure.ac
+++ b/configure.ac
@@ -20,10 +20,6 @@
 AC_PROG_RANLIB
 AM_PROG_CC_C_O
 
-dnl various CFLAGS
-CFLAGS="$CFLAGS -Wall -std=gnu89"
-CFLAGS="$CFLAGS -O0 -g"
-
 dnl Checks for libraries.
 AC_CHECK_LIB(m, main,, AC_MSG_ERROR(maths library is needed))
 dnl AC_CHECK_LIB(dl, main,, AC_CHECK_LIB(c, dlopen,, AC_MSG_ERROR(dl library is needed)))
@@ -35,7 +31,7 @@
 dnl check for mkdir accepting permissions
 AC_MSG_CHECKING(if mkdir rejects permissions)
 ac_mkdir_perm_broken=yes
-AC_TRY_COMPILE([#include <unistd.h>], [mkdir("test", 0777)], [ac_mkdir_perm_broken=no])
+AC_TRY_COMPILE([#include <sys/stat.h>], [mkdir("test", 0777)], [ac_mkdir_perm_broken=no])
 if test x$ac_mkdir_perm_broken = xyes ; then
   AC_DEFINE_UNQUOTED(HAVE_BROKEN_MKDIR, 1, [Defined if mkdir rejects a second permissions parameter.])
 fi