[PATCH][V2] Makfile: add more warning flags to ensure we catch more issues

[Colin King]

From: Colin Ian King <colin.king at canonical.com>

Increase the build warning checks to catch bad code. This builds
with gcc 9.3, gcc 10.0, clang 9 and clang 10 without issues.

Signed-off-by: Colin Ian King <colin.king at canonical.com>
---

V2: remove -Wmissing-format-attribute, I'll try and get that sorted
    for a later release.

---
 src/Makefile.am | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/Makefile.am b/src/Makefile.am
index 904fc020..e0093aef 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -15,7 +15,12 @@ AM_CPPFLAGS = \
 	`pkg-config --silence-errors --cflags json-c`	\
 	-pthread `pkg-config --cflags glib-2.0 gio-2.0` \
 	-Wall -Werror -Wextra				\
-	-Wno-address-of-packed-member
+	-Wno-address-of-packed-member			\
+	-Wfloat-equal -Wmissing-declarations		\
+	-Wno-long-long -Wredundant-decls -Wshadow	\
+	-Wno-missing-field-initializers 		\
+	-Wno-missing-braces -Wno-sign-compare 		\
+	-Wno-multichar -Wcast-qual
 
 bin_PROGRAMS = fwts
 
-- 
2.25.1