gcc: handle the nonnull comparison issue more gracefully.

Signed-off-by: Peter Jones <[email protected]>

gcc.specs

@@ -2,7 +2,7 @@
 + -D_GNU_SOURCE
 
 *efivar_cpp_options:
- -Werror -Wall -std=gnu11 -Wextra -Wno-nonnull-compare
+ -Werror -Wall -std=gnu11 -Wextra
 
 *cpp_options:
 + %(efivar_cpp_options)

src/error.c

@@ -25,6 +25,14 @@
 #include <string.h>
 #include <unistd.h>
 
+/*
+ * GCC complains that we check for null if we have a nonnull attribute, even
+ * though older or other compilers might just ignore that attribute if they
+ * don't support it.  Ugh.
+ */
+#if defined(__GNUC__) && __GNUC__ >= 6
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
 
 typedef struct {
 	int error;

src/include/efivar/efivar-dp.h

@@ -696,6 +696,15 @@ extern int efidp_append_path(const_efidp dp0, const_efidp dp1, efidp *out);
 extern int efidp_append_node(const_efidp dp, const_efidp dn, efidp *out);
 extern int efidp_append_instance(const_efidp dp, const_efidp dpi, efidp *out);
 
+/*
+ * GCC complains that we check for null if we have a nonnull attribute, even
+ * though older or other compilers might just ignore that attribute if they
+ * don't support it.  Ugh.
+ */
+#if defined(__GNUC__) && __GNUC__ >= 6
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
+
 static inline int16_t
 __attribute__((__artificial__))
 __attribute__((__nonnull__(1)))
@@ -999,6 +1008,10 @@ efidp_is_valid(const_efidp dp, ssize_t limit)
 	return 1;
 }
 
+#if defined(__GNUC__) && __GNUC__ >= 6
+#pragma GCC diagnostic pop
+#endif
+
 /* and now, printing and parsing */
 extern ssize_t efidp_parse_device_node(char *path, efidp out, size_t size);
 extern ssize_t efidp_parse_device_path(char *path, efidp out, size_t size);