Clean up more code

- Found some bugs in LLVM compiler-rt library
- The useless LIBC_STUBS package is now deleted
- Improve the overflow checking story even further
- Get chibicc tests working in MODE=dbg mode again
- The libc/isystem/ headers now have correctly named guards

dsp/bmp/bmp.mk

@@ -25,8 +25,7 @@ DSP_BMP_A_CHECKS =				\
 
 DSP_BMP_A_DIRECTDEPS =				\
 	LIBC_NEXGEN32E				\
-	LIBC_TINYMATH				\
-	LIBC_STUBS
+	LIBC_TINYMATH
 
 DSP_BMP_A_DEPS :=				\
 	$(call uniq,$(foreach x,$(DSP_BMP_A_DIRECTDEPS),$($(x))))

dsp/core/core.mk

@@ -20,8 +20,7 @@ DSP_CORE_A_DIRECTDEPS =				\
 	LIBC_MEM				\
 	LIBC_NEXGEN32E				\
 	LIBC_STR				\
-	LIBC_TINYMATH				\
-	LIBC_STUBS
+	LIBC_TINYMATH
 
 DSP_CORE_A_DEPS :=				\
 	$(call uniq,$(foreach x,$(DSP_CORE_A_DIRECTDEPS),$($(x))))

dsp/mpeg/mpeg.mk

@@ -34,7 +34,6 @@ DSP_MPEG_A_DIRECTDEPS =				\
 	LIBC_RUNTIME				\
 	LIBC_STDIO				\
 	LIBC_STR				\
-	LIBC_STUBS				\
 	LIBC_SYSV				\
 	LIBC_TIME				\
 	LIBC_TINYMATH				\

dsp/scale/scale.mk

@@ -31,8 +31,6 @@ DSP_SCALE_A_DIRECTDEPS =			\
 	LIBC_NEXGEN32E				\
 	LIBC_RUNTIME				\
 	LIBC_STR				\
-	LIBC_STUBS				\
-	LIBC_STUBS				\
 	LIBC_TIME				\
 	LIBC_TINYMATH				\
 	LIBC_X

dsp/tty/tty.mk

@@ -35,7 +35,6 @@ DSP_TTY_A_DIRECTDEPS =				\
 	LIBC_NT_KERNEL32			\
 	LIBC_STR				\
 	LIBC_STDIO				\
-	LIBC_STUBS				\
 	LIBC_SOCK				\
 	LIBC_SYSV				\
 	LIBC_TINYMATH				\