Merge pull request #2612 from xrmx/fix-2609

uwsgiconfig: don't add -Wformat-signedness with gcc < 5

uwsgiconfig.py

@@ -688,8 +688,6 @@ def __init__(self, filename, mute=False):
             '-D_LARGEFILE_SOURCE',
             '-D_FILE_OFFSET_BITS=64'
         ]
-        if "gcc" in GCC:
-            cflags.append('-Wformat-signedness')
         self.cflags = cflags + os.environ.get("CFLAGS", "").split() + self.get('cflags', '').split()
 
         python_venv_include = os.path.join(sys.prefix, 'include', 'site',
@@ -770,6 +768,8 @@ def __init__(self, filename, mute=False):
             self.cflags += ['-Wextra', '-Wno-unused-parameter', '-Wno-missing-field-initializers']
         if gcc_major == 4 and gcc_minor < 9:
             self.cflags.append('-Wno-format -Wno-format-security')
+        if "gcc" in GCC and gcc_major >= 5:
+            self.cflags.append('-Wformat-signedness')
 
         self.ldflags = os.environ.get("LDFLAGS", "").split()
         self.libs = ['-lpthread', '-lm', '-rdynamic']