Makefile: Disable warnings to make clang happy

Clang doesn't like some of the warnings we have, so silence the ones we
know about in order to enable the build to succeed. These should be
investigated and removed in once the code issues are resolved.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

Makefile.main

@@ -163,6 +163,17 @@ CFLAGS += -mcpu=pwr8
 LDFLAGS += -mcpu=pwr8
 ASFLAGS += -mcpu=pwr8
 
+# Workarounds
+# TODO: Fix the issues these hide, and remove them
+CFLAGS += -Wno-cast-align \
+	-Wno-unused-command-line-argument \
+	-Wno-unknown-warning-option \
+	-Wno-gnu-variable-sized-type-not-at-end \
+	-Wno-address-of-packed-member
+
+# pci_add_device_nodes is the largest, at 2048 with clang-7 (smaller with older
+# versions)
+CFLAGS += -Wframe-larger-than=2048
 endif
 
 # Special tool flags: