From 849d91bc024f0795a369437f97f8f1e3bb78f9e3 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 24 Oct 2018 20:45:18 +0200
Subject: [PATCH] configure: quit on trying to get ICC and Flex be friends

The CI is using Flex 2.5.35.  And ICC is too picky for it.  Let's stop
making these warnings errors.  I wish I could disable them in the
source files using the ICC version and the Flex version, but ICC's
pragma support is unclear, and I'm tired of fighting it.

* configure.ac (FLEX_SCANNER_CXXFLAGS): Make warnings warnings.
* examples/c++/local.mk: Comment changes.
---
 configure.ac          | 10 +++-------
 examples/c++/local.mk |  2 ++
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index c81446ca..3d55f08c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -162,15 +162,11 @@ if test "$enable_gcc_warnings" = yes; then
   do
     gl_WARN_ADD([$i], [WARN_CXXFLAGS_TEST])
   done
-  # Clang++ 3.2+ rejects C code generated by Flex.
-  gl_WARN_ADD([-Wno-null-conversion], [FLEX_SCANNER_CXXFLAGS])
-  # So does G++ 4.8...
-  gl_WARN_ADD([-Wno-sign-compare], [FLEX_SCANNER_CXXFLAGS])
-  # ... possibly in std=c++11 mode.
-  gl_WARN_ADD([-Wno-zero-as-null-pointer-constant], [FLEX_SCANNER_CXXFLAGS])
-  CXXFLAGS=$save_CXXFLAGS
+  # Too many compilers complain about Flex generated code.
+  gl_WARN_ADD([-Wno-error], [FLEX_SCANNER_CXXFLAGS])
   # Clang++ deprecates compiling C.
   gl_WARN_ADD([-Wno-deprecated], [WNO_DEPRECATED_CXXFLAGS])
+  CXXFLAGS=$save_CXXFLAGS
   AC_LANG_POP([C++])
 fi
 
diff --git a/examples/c++/local.mk b/examples/c++/local.mk
index 4d40abca..b9c2f071 100644
--- a/examples/c++/local.mk
+++ b/examples/c++/local.mk
@@ -46,6 +46,7 @@ endif
 
 check_PROGRAMS += %D%/variant
 nodist_%C%_variant_SOURCES = %D%/variant.yy
+# Don't use gnulib's system headers.
 %C%_variant_CPPFLAGS = -I$(top_builddir)
 dist_TESTS += %D%/variant.test
 %D%/variant.cc: $(BISON_IN) $(dist_pkgdata_DATA)
@@ -54,6 +55,7 @@ if ENABLE_CXX11
   check_PROGRAMS += %D%/variant-11
   nodist_%C%_variant_11_SOURCES = %D%/variant-11.yy
   %C%_variant_11_CXXFLAGS = $(CXX11_CXXFLAGS)
+  # Don't use gnulib's system headers.
   %C%_variant_11_CPPFLAGS = -I$(top_builddir)
   dist_TESTS += %D%/variant-11.test
   %D%/variant-11.cc: $(BISON_IN) $(dist_pkgdata_DATA)