Add configure check for Clang flags for disabling warnings

As suggested in #466.

Also, make --enable-more-warnings actually work when building from a
release archive.

diff --git a/Makefile.in b/Makefile.in
index 0d0916bcfd491fc9ed9a682e1197dae862ddd5e1..aaa5822518186b50ffbfff6fc44ab0d04a86eb15 100644 (file)
--- a/Makefile.in
+++ b/Makefile.in
@@ -132,6 +132,8 @@ clean:
        [ ! -f src/third_party/zstd/Makefile ] || $(MAKE) -C src/third_party/zstd/lib clean
        [ ! -f src/third_party/libb2/Makefile ] || $(MAKE) -C src/third_party/libb2 clean
 
+$(non_third_party_objs) $(test_objs): CFLAGS += @extra_warnings@
+$(non_third_party_objs) $(test_objs): CXXFLAGS += @extra_warnings@
 
 libzstd_options = \
     ZSTD_LEGACY_SUPPORT=0 \

diff --git a/configure.ac b/configure.ac
index 504aede9a96b1b8c935e7f05d14d9eb8a7fbbfeb..2a9640feaa9ac19b65f6147868786a7f49919f09 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -36,8 +36,8 @@ AC_SUBST(disable_cross)
 AC_SUBST(disable_man)
 AC_SUBST(extra_libs)
 AC_SUBST(extra_sources)
+AC_SUBST(extra_warnings)
 AC_SUBST(include_dev_mk)
-AC_SUBST(more_warnings)
 
 m4_include(m4/feature_macros.m4)
 m4_include(m4/ax_cxx_compile_stdcxx.m4)
@@ -64,35 +64,32 @@ else
     CXXFLAGS="$CXXFLAGS -O"
 fi
 
-more_warnings="-Wextra -Wpedantic"
-if test "$ac_compiler_clang" = yes; then
-    more_warnings="$more_warnings -Weverything"
-    more_warnings="$more_warnings -Wno-c++98-compat"
-    more_warnings="$more_warnings -Wno-c++98-compat-pedantic"
-    more_warnings="$more_warnings -Wno-conversion"
-    more_warnings="$more_warnings -Wno-disabled-macro-expansion"
-    more_warnings="$more_warnings -Wno-documentation-unknown-command"
-    more_warnings="$more_warnings -Wno-exit-time-destructors"
-    more_warnings="$more_warnings -Wno-format-nonliteral"
-    more_warnings="$more_warnings -Wno-global-constructors"
-    more_warnings="$more_warnings -Wno-implicit-fallthrough"
-    more_warnings="$more_warnings -Wno-padded"
-    more_warnings="$more_warnings -Wno-shorten-64-to-32"
-    more_warnings="$more_warnings -Wno-sign-conversion"
-    more_warnings="$more_warnings -Wno-undefined-func-template"
-    more_warnings="$more_warnings -Wno-weak-vtables"
-
-# TODO: Enable these in the future:
-    more_warnings="$more_warnings -Wno-old-style-cast"
-    more_warnings="$more_warnings -Wno-zero-as-null-pointer-constant"
-fi
-
 AC_ARG_ENABLE(more_warnings,
   [AS_HELP_STRING([--enable-more-warnings],
     [enable more compiler warnings])])
-if test x${enable_more_warnings} = xyes; then
-    CFLAGS="$CFLAGS $more_warnings"
-    CXXFLAGS="$CXXFLAGS $more_warnings"
+if test "$dev_mode" = yes -o "$enable_more_warnings" = yes; then
+    extra_warnings="-Wextra -Wpedantic"
+    if test "$ac_compiler_clang" = yes; then
+        extra_warnings="$extra_warnings -Weverything"
+        AX_CHECK_COMPILE_FLAG(-Wno-c++98-compat, extra_warnings="$extra_warnings -Wno-c++98-compat")
+        AX_CHECK_COMPILE_FLAG(-Wno-c++98-compat-pedantic, extra_warnings="$extra_warnings -Wno-c++98-compat-pedantic")
+        AX_CHECK_COMPILE_FLAG(-Wno-conversion, extra_warnings="$extra_warnings -Wno-conversion")
+        AX_CHECK_COMPILE_FLAG(-Wno-disabled-macro-expansion, extra_warnings="$extra_warnings -Wno-disabled-macro-expansion")
+        AX_CHECK_COMPILE_FLAG(-Wno-documentation-unknown-command, extra_warnings="$extra_warnings -Wno-documentation-unknown-command")
+        AX_CHECK_COMPILE_FLAG(-Wno-exit-time-destructors, extra_warnings="$extra_warnings -Wno-exit-time-destructors")
+        AX_CHECK_COMPILE_FLAG(-Wno-format-nonliteral, extra_warnings="$extra_warnings -Wno-format-nonliteral")
+        AX_CHECK_COMPILE_FLAG(-Wno-global-constructors, extra_warnings="$extra_warnings -Wno-global-constructors")
+        AX_CHECK_COMPILE_FLAG(-Wno-implicit-fallthrough, extra_warnings="$extra_warnings -Wno-implicit-fallthrough")
+        AX_CHECK_COMPILE_FLAG(-Wno-padded, extra_warnings="$extra_warnings -Wno-padded")
+        AX_CHECK_COMPILE_FLAG(-Wno-shorten-64-to-32, extra_warnings="$extra_warnings -Wno-shorten-64-to-32")
+        AX_CHECK_COMPILE_FLAG(-Wno-sign-conversion, extra_warnings="$extra_warnings -Wno-sign-conversion")
+        AX_CHECK_COMPILE_FLAG(-Wno-undefined-func-template, extra_warnings="$extra_warnings -Wno-undefined-func-template")
+        AX_CHECK_COMPILE_FLAG(-Wno-weak-vtables, extra_warnings="$extra_warnings -Wno-weak-vtables")
+
+        # TODO: Enable these in the future:
+        AX_CHECK_COMPILE_FLAG(-Wno-old-style-cast, extra_warnings="$extra_warnings -Wno-old-style-cast")
+        AX_CHECK_COMPILE_FLAG(-Wno-zero-as-null-pointer-constant, extra_warnings="$extra_warnings -Wno-zero-as-null-pointer-constant")
+    fi
 fi
 
 AC_HEADER_DIRENT

diff --git a/dev.mk.in b/dev.mk.in
index 6d513e9b36fcfbc80d4a0e877c9421959bedeb48..c8527c96d5bb9ff6d7efa7e4b89ac754e0c167ff 100644 (file)
--- a/dev.mk.in
+++ b/dev.mk.in
@@ -171,8 +171,6 @@ docs: $(generated_docs)
        $(Q)$(ASCIIDOC) -a revnumber=$(version) -d manpage -b docbook -o - $< | \
          perl -pe 's!<literal>(.*?)</literal>!<emphasis role="strong">\1</emphasis>!g' >$@
 
-$(non_third_party_objs) $(test_objs): CXXFLAGS += @more_warnings@
-
 doc/ccache.1: doc/MANUAL.xml
        $(if $(quiet),@echo "  A2X      $@")
        $(Q)$(A2X) --doctype manpage --format manpage $<