libretro: Update Makefile, fix ASAN

src/libretro/Makefile

@@ -118,6 +118,39 @@ else ifeq ($(platform), vita)
 	USE_MOTION_SENSOR=1
 	HAVE_NEON=1
 
+# Classic Platforms ####################
+# Platform affix = classic_<ISA>_<µARCH>
+# Help at https://modmyclassic.com/comp
+
+# (armv7 a7, hard point, neon based) ###
+# NESC, SNESC, C64 mini
+else ifeq ($(platform), classic_armv7_a7)
+	TARGET := $(TARGET_NAME)_libretro.so
+	fpic := -fPIC
+	SHARED := -shared
+	TILED_RENDERING = 1
+	CFLAGS += -Ofast \
+	-flto=4 -fwhole-program -fuse-linker-plugin \
+	-fdata-sections -ffunction-sections -Wl,--gc-sections \
+	-fno-stack-protector -fno-ident -fomit-frame-pointer \
+	-falign-functions=1 -falign-jumps=1 -falign-loops=1 \
+	-fno-unwind-tables -fno-asynchronous-unwind-tables -fno-unroll-loops \
+	-fmerge-all-constants -fno-math-errno \
+	-marm -mtune=cortex-a7 -mfpu=neon-vfpv4 -mfloat-abi=hard
+	CXXFLAGS += $(CFLAGS)
+	HAVE_NEON = 1
+	ARCH = arm
+	ifeq ($(shell echo `$(CC) -dumpversion` "< 4.9" | bc -l), 1)
+	  CFLAGS += -march=armv7-a
+	else
+	  CFLAGS += -march=armv7ve
+	  # If gcc is 5.0 or later
+	  ifeq ($(shell echo `$(CC) -dumpversion` ">= 5" | bc -l), 1)
+	    LDFLAGS += -static-libgcc -static-libstdc++
+	  endif
+	endif
+#######################################
+
 # Windows MSVC 2017 all architectures
 else ifneq (,$(findstring windows_msvc2017,$(platform)))
 
@@ -233,8 +266,9 @@ VBA_DEFINES += -DFRONTEND_SUPPORTS_RGB565
 endif
 
 ifneq ($(SANITIZER),)
-   CFLAGS   += -fsanitize=$(SANITIZER)
-   LDFLAGS  += -fsanitize=$(SANITIZER)
+   CFLAGS += -fsanitize=$(SANITIZER)
+   CXXFLAGS += -fsanitize=$(SANITIZER)
+   LDFLAGS += -fsanitize=$(SANITIZER)
 endif
 
 ifeq ($(DEBUG), 1)