Don't force LTO, -Werror, or _F_S=2 (Gentoo defaults to >=2).
--- a/configure.ac
+++ b/configure.ac
@@ -46,10 +46,6 @@ AC_DEFUN([AC_CHECK_CFLAG], [
 	CFLAGS="$HOLD"
 ])
 
-AC_CHECK_CFLAG([[-flto=auto]])
-AC_CHECK_CFLAG([[-fstack-clash-protection]])
-AC_CHECK_CFLAG([[-fstack-protector-strong]])
-
 #
 # Support for check unit tests
 #
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -11,10 +11,7 @@ AM_CFLAGS = \
 	-DSYSCONFDIR=\"$(sysconfdir)\" \
 	-DYY_NO_INPUT \
 	-DYY_NO_UNPUT \
-	-D_FORTIFY_SOURCE=2 \
-	-Wall \
-	-Werror
-
+	-Wall
 #
 #
 #
--- a/tests/unit/Makefile.am
+++ b/tests/unit/Makefile.am
@@ -7,9 +7,7 @@ AM_CFLAGS = \
 	@CHECK_CFLAGS@ \
 	-DYY_NO_INPUT \
 	-DYY_NO_UNPUT \
-	-D_FORTIFY_SOURCE=2 \
-	-Wall \
-	-Werror
+	-Wall
 
 AM_LDFLAGS = \
 	$(top_builddir)/src/builtin_table.o \