more errors ...

[ghost]

gcc -v

Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/i686-pc-linux-gnu/4.6.4/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ./configure --prefix=/usr
Thread model: posix
gcc version 4.6.4 (GCC)

make | grep warning

jsarray.c: In function 'Ap_join':
jsarray.c:95:14: warning: variable 'sep' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
jsarray.c:97:15: warning: variable 'seplen' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
jsdump.c: In function 'js_dumpvalue':
jsdump.c:808:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:809:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:815:5: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:818:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'js_CFunction' [-Wformat]
jsdump.c:823:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:827:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsfunction.c: In function 'jsB_Function':
jsfunction.c:11:14: warning: variable 'body' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
jsstring.c: In function 'Sp_concat':
jsstring.c:103:15: warning: variable 'n' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
regex.c: In function 'compile':
regex.c:686:14: warning: 'inst' may be used uninitialized in this function [-Wuninitialized]
regex.c: In function 'lex':
regex.c:279:13: warning: 'save' may be used uninitialized in this function [-Wuninitialized]
regex.c:248:7: note: 'save' was declared here
In file included from one.c:7:0:
jsdump.c: In function 'js_dumpvalue':
jsdump.c:808:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:809:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:815:5: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:818:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'js_CFunction' [-Wformat]
jsdump.c:823:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
jsdump.c:827:3: warning: format '%p' expects argument of type 'void *', but argument 2 has type 'struct js_Object *' [-Wformat]
In file included from one.c:24:0:
regex.c: In function 'lex':
regex.c:279:13: warning: 'save' may be used uninitialized in this function [-Wuninitialized]
regex.c:248:7: note: 'save' was declared here
regex.c: In function 'compile':
regex.c:686:14: warning: 'inst' may be used uninitialized in this function [-Wuninitialized]
In file included from one.c:22:0:
jsstring.c: In function 'Sp_concat':
jsstring.c:103:15: warning: variable 'n' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
In file included from one.c:23:0:
jsvalue.c: In function 'js_instanceof':
jsrun.c:155:14: warning: assuming signed overflow does not occur when assuming that (X - c) > X is always false [-Wstrict-overflow]
In file included from one.c:1:0:
jsarray.c: In function 'Ap_join':
jsarray.c:95:14: warning: variable 'sep' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
jsarray.c:97:15: warning: variable 'seplen' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
jsarray.c: In function 'Ap_sort':
jsrun.c:155:14: warning: assuming signed overflow does not occur when assuming that (X - c) > X is always false [-Wstrict-overflow]
In file included from one.c:9:0:
jsfunction.c: In function 'jsB_Function':
jsfunction.c:11:14: warning: variable 'body' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]

[ghost]

CFLAGS := -std=gnu99 -D_GNU_SOURCE -DLINUX -Wall

regex.c: In function 'lexclass':
regex.c:248:14: warning: initialization makes integer from pointer without a cast [enabled by default]
regex.c: In function 'compile':
regex.c:686:14: warning: 'inst' may be used uninitialized in this function [-Wuninitialized]

[ccxvii]

gcc is notoriously bad about tracking control flow when compiling with optimizations and setjmp/longjmp is involved. these warnings are harmless, and a better compiler like clang won't get confused by the same code.