X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=configure.ac;h=3b007c5d29b51404c86d151d222ea5136acf31c5;hb=488159627f4f579a80b71c5f7713126864d5623f;hp=f660e60ebdf7833167557a4b3fd8ec66132f65b3;hpb=7f9856c5dace35f8efe5a20ee1013815e67b9550;p=coloredstderr%2Fcoloredstderr.git

diff --git a/configure.ac b/configure.ac
index f660e60..3b007c5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -32,6 +32,10 @@ dnl Used by test suite.
 AC_PROG_SED
 AC_PROG_EGREP
 
+if test "x$GCC" = xyes; then
+    CFLAGS="-Wall -Wextra -Wconversion $CFLAGS"
+fi
+
 AC_CHECK_HEADERS([fcntl.h error.h])
 
 AC_TYPE_PID_T
@@ -39,10 +43,19 @@ AC_TYPE_SIZE_T
 AC_TYPE_SSIZE_T
 
 AC_C_INLINE
+AX_C___ATTRIBUTE__
 
 AC_FUNC_FORK
 AC_CHECK_FUNCS([dup2 memmove setenv strdup])
 
+dnl Thanks to gperftools' configure.ac (https://code.google.com/p/gperftools).
+AC_MSG_CHECKING([for __builtin_expect])
+AC_LINK_IFELSE([AC_LANG_PROGRAM([],[return __builtin_expect(main != 0, 1)])],
+               [AC_DEFINE([HAVE___BUILTIN_EXPECT], 1,
+                          [Define to 1 if the compiler supports __builtin_expect().])
+                AC_MSG_RESULT([yes])],
+               [AC_MSG_RESULT([no])])
+
 AC_SEARCH_LIBS([dlsym], [dl], [], [AC_MSG_ERROR([dlsym() is required])])
 
 AC_ARG_ENABLE([debug],