ada/spark: all warnings, warn strict, style checks

* enable all common warnings through default value of CC_ADA_WARN
* treat warnings like errors through default value of CC_ADA_WARN_STRICT
* enable almost all style checks through default value of CC_ADA_WARN_STRICT
* style fixes for aes_cbc_4k
* disable strict warnings and style checks for libsparkcrypto and spark lib

Ref #3848

repos/base/mk/generic.mk

@@ -82,6 +82,16 @@ CUSTOM_ADA_FLAGS   ?= --RTS=$(ADA_RTS)
 CUSTOM_ADA_OPT     ?= $(CC_ADA_OPT) -gnatef
 CUSTOM_ADA_INCLUDE ?= -I- $(INCLUDES)
 
+#
+# The files generated by the binder would not pass our GNAT style checks
+# thus we handle them separately and disable style checks via compiler option
+# '-gnatyN'
+#
+b~%.ali b~%.o: b~%.adb
+	$(MSG_COMP)$@
+	$(VERBOSE)$(CUSTOM_ADA_CC) $(CUSTOM_ADA_FLAGS) $(CUSTOM_ADA_OPT) -gnatyN $(CUSTOM_ADA_INCLUDE) -c $<
+	$(VERBOSE)$(ALI2DEP) $(dir $<) $(ALL_INC_DIR) b~$*.ali
+
 %.ali %.o: %.adb
 	$(MSG_COMP)$@
 	$(VERBOSE)$(CUSTOM_ADA_CC) $(CUSTOM_ADA_FLAGS) $(CUSTOM_ADA_OPT) $(CUSTOM_ADA_INCLUDE) -c $<

repos/base/mk/global.mk

@@ -146,6 +146,12 @@ CC_WARN += -Wno-error=implicit-fallthrough
 CC_CXX_WARN_STRICT ?= -Wextra -Weffc++ -Werror -Wsuggest-override
 CC_CXX_WARN        ?= $(CC_WARN) $(CC_CXX_WARN_STRICT)
 
+#
+# Additional warnings for Ada/SPARK
+#
+CC_ADA_WARN_STRICT ?= -gnatwe -gnatyyBdSux
+CC_ADA_WARN        ?= -gnatwa $(CC_ADA_WARN_STRICT)
+
 #
 # Aggregate compiler options that are common for C and C++
 #
@@ -174,7 +180,9 @@ CC_OPT     += $(CC_OPT_PIC)
 #
 CC_CXX_OPT += $(CC_OPT) $(CC_CXX_WARN)
 CC_C_OPT   += $(CC_OPT)
-CC_ADA_OPT += $(filter-out -fno-builtin-cos -fno-builtin-sin -fno-builtin-cosf -fno-builtin-sinf ,$(CC_OPT)) -fexceptions
+CC_ADA_OPT += $(CC_ADA_WARN) -fexceptions
+CC_ADA_OPT += $(filter-out -fno-builtin-cos -fno-builtin-sin \
+                           -fno-builtin-cosf -fno-builtin-sinf ,$(CC_OPT))
 
 #
 # Enable C++11 by default