[PATCH 3/4] ell: Fix cert_pkcs12_pbkdf() warning under Alpine/clang

Disable GCC specific warning under clang.

../ell/cert-crypto.c:235:1: warning: unknown warning group '-Wmaybe-uninitialized', ignored [-Wunknown-warning-option]
  235 | _Pragma("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
      | ^
<scratch space>:28:25: note: expanded from here
   28 |  GCC diagnostic ignored "-Wmaybe-uninitialized"
      |                         ^
1 warning generated.
../ell/cert-crypto.c:235:1: warning: unknown warning group '-Wmaybe-uninitialized', ignored [-Wunknown-warning-option]
  235 | _Pragma("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
      | ^
<scratch space>:28:25: note: expanded from here
   28 |  GCC diagnostic ignored "-Wmaybe-uninitialized"
      |                         ^
1 warning generated.
---
 ell/cert-crypto.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/ell/cert-crypto.c b/ell/cert-crypto.c
index d6babe007d1c..de416050bfb5 100644
--- a/ell/cert-crypto.c
+++ b/ell/cert-crypto.c
@@ -231,8 +231,10 @@ uint8_t *cert_pkcs12_pbkdf(const char *password,
 		ptr += s_len + salt_len - j;
 	}
 
+#if defined(__GNUC__) && !defined(__clang__)
 _Pragma("GCC diagnostic push")
 _Pragma("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
+#endif /* gcc && !clang */
 	if (p_len) {
 		for (j = passwd_len; j < p_len;
 					j += passwd_len, ptr += passwd_len)
@@ -243,7 +245,9 @@ _Pragma("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
 		explicit_bzero(bmpstring, passwd_len);
 		l_free(bmpstring);
 	}
+#if defined(__GNUC__) && !defined(__clang__)
 _Pragma("GCC diagnostic pop")
+#endif /* gcc && !clang */
 
 	key = l_malloc(key_len + hash->len);
 
-- 
2.53.0