configure: relax to C99 for regular users.

The code will continue to stick to C90, but requesting C90
compatibility from GCC may break for downstream users in some
environments that don't support C90 in their header files.

* configure (lang_flags): Remove -ansi option from here.
(usage): Help text for maintainer mode updated.
(mainline): Add -std=c++98 to the front of lang_flags if
compiling as C++, -std=c90 in maintainer mode, else -std=c99.

1 files changed, 9 insertions, 2 deletions

diff --git a/configure b/configure
index c801a86c..75fd7591 100755
--- a/configure
+++ b/configure
@@ -158,7 +158,7 @@ yacc_given=
 yacc_is_newer_bison=
 nm='$(cross)$(tool_prefix)nm'
 opt_flags='-O2 -fno-stack-protector'
-lang_flags='-ansi -D_XOPEN_SOURCE=700 -D_POSIX_C_SOURCE=200112 -D_GNU_SOURCE'
+lang_flags='-D_XOPEN_SOURCE=700 -D_POSIX_C_SOURCE=200112 -D_GNU_SOURCE'
 diag_flags="-Wall -Wextra -Werror=implicit-function-declaration \
            -Werror=missing-prototypes -Werror=strict-prototypes \
            -Werror=old-style-declaration -Werror=old-style-definition"
@@ -323,7 +323,8 @@ maintainer [$maintainer]
   mode, otherwise the build is configured for user mode. In maintainer mode,
   the scanner and parser generator tools are expected to be available.
   In user mode, the shipped parser and scanner are used. Changes to
-  the parser.l and parser.y files will have no effect.
+  the parser.l and parser.y files will have no effect. In maintainer mode,
+  also, c90 is used if compiling the code as C.
 
 prefix [$prefix]
 
@@ -779,8 +780,14 @@ if [ $cplusplus ] ; then
      diag_flags="$diag_flags $flag"
    done
    diag_flags=${diag_flags# }
+   lang_flags="-std=c++98 $lang_flags"
 else
    printf "no\n"
+   if [ $maintainer ] ; then
+     lang_flags="-std=c90 $lang_flags"
+   else
+     lang_flags="-std=c99 $lang_flags"
+   fi
 fi
 
 gen_config_make()