Use -Werror in external/wpa_supplicant_8

* Suppress existing non-critical warnings.
* Keep sometimes-uninitialized warnings to be fixed later.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Ifa81e3916a00c5b728c604f3c20852ed087c3080
diff --git a/wpa_supplicant/Android.mk b/wpa_supplicant/Android.mk
index 41ba954..2165382 100644
--- a/wpa_supplicant/Android.mk
+++ b/wpa_supplicant/Android.mk
@@ -22,6 +22,27 @@
 # Set Android log name
 L_CFLAGS += -DANDROID_LOG_NAME=\"wpa_supplicant\"
 
+L_CFLAGS += -Wall -Werror
+
+# Keep sometimes uninitialized warnings
+L_CFLAGS += -Wno-error-sometimes-uninitialized
+
+# Disable incompatible pointer type warnings
+L_CFLAGS += -Wno-incompatible-pointer-types
+L_CFLAGS += -Wno-incompatible-pointer-types-discards-qualifiers
+
+# Disable extraneous parentheses warnings
+L_CFLAGS += -Wno-parentheses-equality
+
+# Disable sign compare warnings
+L_CFLAGS += -Wno-sign-compare
+
+# Disable unused function warnings
+L_CFLAGS += -Wno-unused-function
+
+# Disable unused variable warnings
+L_CFLAGS += -Wno-unused-variable
+
 # Disable unused parameter warnings
 L_CFLAGS += -Wno-unused-parameter