lib/posix-environ: Remove unused variable warnings

If an environment variable is not set, the
`DECLARE_LIBPOSIX_ENVIRON_ENV_VAR` macros end up declaring unused
global variables which generate warnings.

To solve this, guard the use of these macros so that they are not used
for a particular unset environment variable.

Signed-off-by: Sergiu Moga <sergiu@unikraft.io>
Reviewed-by: Michalis Pappas <michalis@unikraft.io>
Approved-by: Simon Kuenzer <simon@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #1058

diff --git a/lib/posix-environ/environ.c b/lib/posix-environ/environ.c
index fa6958b693aef777f03f6dca5c201ec81127e7b9..f2b254892b48e3944b7da0191b1544ae615903d8 100644 (file)
--- a/lib/posix-environ/environ.c
+++ b/lib/posix-environ/environ.c
@@ -14,22 +14,54 @@
                                CONFIG_LIBPOSIX_ENVIRON_ENVP##x
 
 
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP0_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(0);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP0_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP1_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(1);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP1_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP2_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(2);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP2_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP3_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(3);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP3_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP4_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(4);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP4_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP5_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(5);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP5_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP6_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(6);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP6_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP7_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(7);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP7_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP8_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(8);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP8_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP9_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(9);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP9_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP10_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(10);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP10_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP11_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(11);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP11_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP12_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(12);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP12_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP13_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(13);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP13_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP14_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(14);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP14_NOTEMPTY */
+#if CONFIG_LIBPOSIX_ENVIRON_ENVP15_NOTEMPTY
 DECLARE_LIBPOSIX_ENVIRON_ENV_VAR(15);
+#endif /* CONFIG_LIBPOSIX_ENVIRON_ENVP15_NOTEMPTY */
 
 /*
  * Size the array