meson: fix typo in compiler flag

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
diff --git a/meson.build b/meson.build
index 1d7b786..bdfec81 100644
--- a/meson.build
+++ b/meson.build
@@ -192,7 +192,7 @@
 
 warn_c_args = []
 foreach a : ['-Wall', '-Wextra', '-Wsign-compare', '-Werror=undef',
-             '-Werror-implicit-function-declaration', '-Wpointer-arith',
+             '-Werror=implicit-function-declaration', '-Wpointer-arith',
              '-Wwrite-strings', '-Wstrict-prototypes', '-Wmissing-prototypes',
              '-Wmissing-declarations', '-Wnested-externs', '-Wpacked',
              '-Wswitch-enum', '-Wmissing-format-attribute',