meson: tell flex that we support c99

flexint.h uses stdint.h if the compiler claims to support C99. MSVC
doesn't support enough of C99 to enable this flag, but it supports
enough to keep flex happy.

Without this, we end up with *both* some flex-specific definitions as
well as our own definitions from mesa-headers, producing a slew of
compiler warnings.

Reviewed-by: Brian Paul <brianp@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4577>

diff --git a/meson.build b/meson.build
index 6b85c95..9184b69 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -1506,7 +1506,7 @@ if host_machine.system() == 'windows'
   if prog_flex.found()
     # windows compatibility (uses <io.h> instead of <unistd.h> and _isatty,
     # _fileno functions)
-    prog_flex = [prog_flex, '--wincompat']
+    prog_flex = [prog_flex, '--wincompat', '-D__STDC_VERSION__=199901']
   else
     prog_flex = [find_program('lex', 'flex', required : with_any_opengl)]
   endif