configure option `--enable-warnings' and `WARNINGFLAGS'

`WARNINGFLAGS' can be passed when invoking `configure'
 and when invoking `make'

if configure switch `--enable-warnings' was given
  then default to something useful if we have `GCC'

`WARNINGFLAGS' is not used when compiling `stage1flex'
  to avoid unnecessary clutter

diff --git a/configure.ac b/configure.ac
index 2bfdd1ebb1a2f1bdab673e1118aff31bd9aa15e8..14dfea1718c714db4d1eae4424452b49ef39d751 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -48,6 +48,18 @@ AC_PROG_LN_S
 AC_PROG_AWK
 AC_PROG_INSTALL
 
+# allow passing a variable `WARNINGFLAGS',
+#   either when invoking `configure', or when invoking `make'
+# default to something useful if GCC was detected
+
+AC_ARG_ENABLE([warnings],
+  [AS_HELP_STRING([--enable-warnings],
+                  [enable a bunch of compiler warning flags (defaults to GCC warning flags).])],
+  [AS_IF([test "x$GCC" == xyes],
+    [ : ${WARNINGFLAGS="-Wall -Wextra -Wmissing-prototypes -Wstrict-prototypes -Wnested-externs -Wold-style-definition -Wredundant-decls -Wconversion -Wno-unused-but-set-variable"} ])])
+
+AC_SUBST([WARNINGFLAGS])
+
 AC_PATH_PROG([BISON], bison, no)
 AS_IF([test "$BISON" != no],[],
        [ AC_SUBST([BISON], [\${top_srcdir}/build-aux/missing bison])

diff --git a/src/Makefile.am b/src/Makefile.am
index adfbbf3293cc63f7b4d279dd2bf755637d470b05..f8354ed2a9fa2cfd02d09a39992077ffb9ad1070 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -15,10 +15,14 @@ stage1flex_SOURCES = \
        scan.l \
        $(COMMON_SOURCES)
 
+stage1flex_CFLAGS = $(AM_CFLAGS)
+
 flex_SOURCES = \
        stage1scan.l \
        $(COMMON_SOURCES)
 
+flex_CFLAGS = $(AM_CFLAGS) $(WARNINGFLAGS)
+
 COMMON_SOURCES = \
        buf.c \
        ccl.c \

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 428e4b25c86b1834b3d343d212e64dede9599496..817f1a354979a9ce9b42eff71018465a7ecd38f6 100644 (file)
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -19,6 +19,8 @@
 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 # PURPOSE.
 
+AM_CFLAGS = $(WARNINGFLAGS)
+
 TESTS = $(check_PROGRAMS) options.cn
 
 # The script testwrapper.sh will run most tests as is. A couple tests