Fix build errors by testing for compiler flags #31

dharple · Feb 13, 2021 · 07df16c · 07df16c
1 parent 9d030b8
commit 07df16c
Show file tree

Hide file tree

Showing 3 changed files with 161 additions and 7 deletions.
diff --git a/configure b/configure
@@ -3789,6 +3789,122 @@ fi
 done
 
 
+#
+# References and reasons for compiler flags:
+#
+# https://github.com/klange/prboom/blob/master/autotools/ac_c_compile_flags.m4
+# https://github.com/dharple/detox/issues/31
+# https://www.keil.com/support/man/docs/armclang_ref/armclang_ref_cjh1548250046139.htm
+# https://developers.redhat.com/blog/2020/05/22/stack-clash-mitigation-in-gcc-part-3/
+# https://gcc.gnu.org/onlinedocs/gccint/LTO-Overview.html
+#
+
+
+
+
+	HOLD="$CFLAGS"
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether compiler supports -flto=auto" >&5
+$as_echo_n "checking whether compiler supports -flto=auto... " >&6; }
+	CFLAGS="$HOLD -flto=auto"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+			HOLD="$CFLAGS"
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+
+else
+
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	CFLAGS="$HOLD"
+
+
+	HOLD="$CFLAGS"
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether compiler supports -fstack-clash-protection" >&5
+$as_echo_n "checking whether compiler supports -fstack-clash-protection... " >&6; }
+	CFLAGS="$HOLD -fstack-clash-protection"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+			HOLD="$CFLAGS"
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+
+else
+
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	CFLAGS="$HOLD"
+
+
+	HOLD="$CFLAGS"
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether compiler supports -fstack-protector-strong" >&5
+$as_echo_n "checking whether compiler supports -fstack-protector-strong... " >&6; }
+	CFLAGS="$HOLD -fstack-protector-strong"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+			HOLD="$CFLAGS"
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+
+else
+
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	CFLAGS="$HOLD"
+
+
+#
+#
+#
+
 ac_config_headers="$ac_config_headers src/config.h"
 
 ac_config_files="$ac_config_files Makefile src/Makefile"

diff --git a/configure.ac b/configure.ac
@@ -8,6 +8,44 @@ AC_PROG_YACC
 
 AC_CHECK_FUNCS([getopt_long])
 
+#
+# References and reasons for compiler flags:
+#
+# https://github.com/klange/prboom/blob/master/autotools/ac_c_compile_flags.m4
+# https://github.com/dharple/detox/issues/31
+# https://www.keil.com/support/man/docs/armclang_ref/armclang_ref_cjh1548250046139.htm
+# https://developers.redhat.com/blog/2020/05/22/stack-clash-mitigation-in-gcc-part-3/
+# https://gcc.gnu.org/onlinedocs/gccint/LTO-Overview.html
+#
+
+AC_DEFUN([AC_CHECK_CFLAG], [
+	HOLD="$CFLAGS"
+	AC_MSG_CHECKING(whether compiler supports $1)
+	CFLAGS="$HOLD $1"
+	AC_COMPILE_IFELSE(
+		[AC_LANG_PROGRAM(
+			[[]], 
+			[[]]
+		)],
+		[
+			HOLD="$CFLAGS"
+			AC_MSG_RESULT(yes)
+		],
+		[
+			AC_MSG_RESULT(no)
+		]
+	)
+	CFLAGS="$HOLD"
+])
+
+AC_CHECK_CFLAG([[-flto=auto]])
+AC_CHECK_CFLAG([[-fstack-clash-protection]])
+AC_CHECK_CFLAG([[-fstack-protector-strong]])
+
+#
+#
+#
+
 AC_CONFIG_HEADER([src/config.h])
 AC_CONFIG_FILES([
  Makefile

diff --git a/src/Makefile.am b/src/Makefile.am
@@ -1,10 +1,9 @@
+#
 # References and reasons for compiler flags:
 #
 # https://github.com/dharple/detox/issues/31
 # https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html
-# https://www.keil.com/support/man/docs/armclang_ref/armclang_ref_cjh1548250046139.htm
-# https://developers.redhat.com/blog/2020/05/22/stack-clash-mitigation-in-gcc-part-3/
-# https://gcc.gnu.org/onlinedocs/gccint/LTO-Overview.html
+# https://access.redhat.com/blogs/766093/posts/1976213
 #
 
 AM_CFLAGS = \
@@ -14,10 +13,11 @@ AM_CFLAGS = \
 	-DYY_NO_UNPUT \
 	-D_FORTIFY_SOURCE=2 \
 	-Wall \
-	-Werror=return-type \
-	-flto=auto \
-	-fstack-clash-protection \
-	-fstack-protector-strong
+	-Werror
+
+#
+#
+#
 
 AM_YFLAGS = -d