improve the libc of wasm32-freestanding target

 * introduce wasm32-freestanding-musl .h files to fix
   conflicts with stddef.h and errno.h
 * fix an issue with zig build system regarding installation of
   webassembly libraries
 * add implementations to zig's libc:
   - strcmp
   - strncmp
   - strerror
   - strlen

See #514

Author: andrewrk

CMakeLists.txt

@@ -6066,6 +6066,8 @@ set(ZIG_LIBC_FILES
     "include/x86_64-linux-musl/bits/stat.h"
     "include/x86_64-linux-musl/bits/syscall.h"
     "include/x86_64-linux-musl/bits/user.h"
+    "include/wasm32-freestanding-musl/bits/alltypes.h"
+    "include/wasm32-freestanding-musl/errno.h"
     "musl/arch/aarch64/atomic_arch.h"
     "musl/arch/aarch64/bits/alltypes.h.in"
     "musl/arch/aarch64/bits/endian.h"

libc/include/wasm32-freestanding-musl/bits/alltypes.h

@@ -0,0 +1,385 @@
+#define _Addr long
+#define _Int64 long long
+#define _Reg long
+
+#if defined(__NEED_va_list) && !defined(__DEFINED_va_list)
+typedef __builtin_va_list va_list;
+#define __DEFINED_va_list
+#endif
+
+#if defined(__NEED___isoc_va_list) && !defined(__DEFINED___isoc_va_list)
+typedef __builtin_va_list __isoc_va_list;
+#define __DEFINED___isoc_va_list
+#endif
+
+
+#ifndef __cplusplus
+#if defined(__NEED_wchar_t) && !defined(__DEFINED_wchar_t)
+typedef int wchar_t;
+#define __DEFINED_wchar_t
+#endif
+
+#endif
+
+#if defined(__NEED_float_t) && !defined(__DEFINED_float_t)
+typedef float float_t;
+#define __DEFINED_float_t
+#endif
+
+#if defined(__NEED_double_t) && !defined(__DEFINED_double_t)
+typedef double double_t;
+#define __DEFINED_double_t
+#endif
+
+
+#if defined(__NEED_max_align_t) && !defined(__DEFINED_max_align_t)
+typedef struct { long long __ll; long double __ld; } max_align_t;
+#define __DEFINED_max_align_t
+#endif
+
+
+#if defined(__NEED_time_t) && !defined(__DEFINED_time_t)
+typedef long time_t;
+#define __DEFINED_time_t
+#endif
+
+#if defined(__NEED_suseconds_t) && !defined(__DEFINED_suseconds_t)
+typedef long suseconds_t;
+#define __DEFINED_suseconds_t
+#endif
+
+
+#if defined(__NEED_pthread_attr_t) && !defined(__DEFINED_pthread_attr_t)
+typedef struct { union { int __i[9]; volatile int __vi[9]; unsigned __s[9]; } __u; } pthread_attr_t;
+#define __DEFINED_pthread_attr_t
+#endif
+
+#if defined(__NEED_pthread_mutex_t) && !defined(__DEFINED_pthread_mutex_t)
+typedef struct { union { int __i[6]; volatile int __vi[6]; volatile void *volatile __p[6]; } __u; } pthread_mutex_t;
+#define __DEFINED_pthread_mutex_t
+#endif
+
+#if defined(__NEED_mtx_t) && !defined(__DEFINED_mtx_t)
+typedef struct { union { int __i[6]; volatile int __vi[6]; volatile void *volatile __p[6]; } __u; } mtx_t;
+#define __DEFINED_mtx_t
+#endif
+
+#if defined(__NEED_pthread_cond_t) && !defined(__DEFINED_pthread_cond_t)
+typedef struct { union { int __i[12]; volatile int __vi[12]; void *__p[12]; } __u; } pthread_cond_t;
+#define __DEFINED_pthread_cond_t
+#endif
+
+#if defined(__NEED_cnd_t) && !defined(__DEFINED_cnd_t)
+typedef struct { union { int __i[12]; volatile int __vi[12]; void *__p[12]; } __u; } cnd_t;
+#define __DEFINED_cnd_t
+#endif
+
+#if defined(__NEED_pthread_rwlock_t) && !defined(__DEFINED_pthread_rwlock_t)
+typedef struct { union { int __i[8]; volatile int __vi[8]; void *__p[8]; } __u; } pthread_rwlock_t;
+#define __DEFINED_pthread_rwlock_t
+#endif
+
+#if defined(__NEED_pthread_barrier_t) && !defined(__DEFINED_pthread_barrier_t)
+typedef struct { union { int __i[5]; volatile int __vi[5]; void *__p[5]; } __u; } pthread_barrier_t;
+#define __DEFINED_pthread_barrier_t
+#endif
+
+#if defined(__NEED_size_t) && !defined(__DEFINED_size_t)
+typedef unsigned _Addr size_t;
+#define __DEFINED_size_t
+#endif
+
+#if defined(__NEED_uintptr_t) && !defined(__DEFINED_uintptr_t)
+typedef unsigned _Addr uintptr_t;
+#define __DEFINED_uintptr_t
+#endif
+
+#if defined(__NEED_ptrdiff_t) && !defined(__DEFINED_ptrdiff_t)
+typedef _Addr ptrdiff_t;
+#define __DEFINED_ptrdiff_t
+#endif
+
+#if defined(__NEED_ssize_t) && !defined(__DEFINED_ssize_t)
+typedef _Addr ssize_t;
+#define __DEFINED_ssize_t
+#endif
+
+#if defined(__NEED_intptr_t) && !defined(__DEFINED_intptr_t)
+typedef _Addr intptr_t;
+#define __DEFINED_intptr_t
+#endif
+
+#if defined(__NEED_regoff_t) && !defined(__DEFINED_regoff_t)
+typedef _Addr regoff_t;
+#define __DEFINED_regoff_t
+#endif
+
+#if defined(__NEED_register_t) && !defined(__DEFINED_register_t)
+typedef _Reg register_t;
+#define __DEFINED_register_t
+#endif
+
+
+#if defined(__NEED_int8_t) && !defined(__DEFINED_int8_t)
+typedef signed char     int8_t;
+#define __DEFINED_int8_t
+#endif
+
+#if defined(__NEED_int16_t) && !defined(__DEFINED_int16_t)
+typedef signed short    int16_t;
+#define __DEFINED_int16_t
+#endif
+
+#if defined(__NEED_int32_t) && !defined(__DEFINED_int32_t)
+typedef signed int      int32_t;
+#define __DEFINED_int32_t
+#endif
+
+#if defined(__NEED_int64_t) && !defined(__DEFINED_int64_t)
+typedef signed _Int64   int64_t;
+#define __DEFINED_int64_t
+#endif
+
+#if defined(__NEED_intmax_t) && !defined(__DEFINED_intmax_t)
+typedef signed _Int64   intmax_t;
+#define __DEFINED_intmax_t
+#endif
+
+#if defined(__NEED_uint8_t) && !defined(__DEFINED_uint8_t)
+typedef unsigned char   uint8_t;
+#define __DEFINED_uint8_t
+#endif
+
+#if defined(__NEED_uint16_t) && !defined(__DEFINED_uint16_t)
+typedef unsigned short  uint16_t;
+#define __DEFINED_uint16_t
+#endif
+
+#if defined(__NEED_uint32_t) && !defined(__DEFINED_uint32_t)
+typedef unsigned int    uint32_t;
+#define __DEFINED_uint32_t
+#endif
+
+#if defined(__NEED_uint64_t) && !defined(__DEFINED_uint64_t)
+typedef unsigned _Int64 uint64_t;
+#define __DEFINED_uint64_t
+#endif
+
+#if defined(__NEED_u_int64_t) && !defined(__DEFINED_u_int64_t)
+typedef unsigned _Int64 u_int64_t;
+#define __DEFINED_u_int64_t
+#endif
+
+#if defined(__NEED_uintmax_t) && !defined(__DEFINED_uintmax_t)
+typedef unsigned _Int64 uintmax_t;
+#define __DEFINED_uintmax_t
+#endif
+
+
+#if defined(__NEED_mode_t) && !defined(__DEFINED_mode_t)
+typedef unsigned mode_t;
+#define __DEFINED_mode_t
+#endif
+
+#if defined(__NEED_nlink_t) && !defined(__DEFINED_nlink_t)
+typedef unsigned _Reg nlink_t;
+#define __DEFINED_nlink_t
+#endif
+
+#if defined(__NEED_off_t) && !defined(__DEFINED_off_t)
+typedef _Int64 off_t;
+#define __DEFINED_off_t
+#endif
+
+#if defined(__NEED_ino_t) && !defined(__DEFINED_ino_t)
+typedef unsigned _Int64 ino_t;
+#define __DEFINED_ino_t
+#endif
+
+#if defined(__NEED_dev_t) && !defined(__DEFINED_dev_t)
+typedef unsigned _Int64 dev_t;
+#define __DEFINED_dev_t
+#endif
+
+#if defined(__NEED_blksize_t) && !defined(__DEFINED_blksize_t)
+typedef long blksize_t;
+#define __DEFINED_blksize_t
+#endif
+
+#if defined(__NEED_blkcnt_t) && !defined(__DEFINED_blkcnt_t)
+typedef _Int64 blkcnt_t;
+#define __DEFINED_blkcnt_t
+#endif
+
+#if defined(__NEED_fsblkcnt_t) && !defined(__DEFINED_fsblkcnt_t)
+typedef unsigned _Int64 fsblkcnt_t;
+#define __DEFINED_fsblkcnt_t
+#endif
+
+#if defined(__NEED_fsfilcnt_t) && !defined(__DEFINED_fsfilcnt_t)
+typedef unsigned _Int64 fsfilcnt_t;
+#define __DEFINED_fsfilcnt_t
+#endif
+
+
+#if defined(__NEED_wint_t) && !defined(__DEFINED_wint_t)
+typedef unsigned wint_t;
+#define __DEFINED_wint_t
+#endif
+
+#if defined(__NEED_wctype_t) && !defined(__DEFINED_wctype_t)
+typedef unsigned long wctype_t;
+#define __DEFINED_wctype_t
+#endif
+
+
+#if defined(__NEED_timer_t) && !defined(__DEFINED_timer_t)
+typedef void * timer_t;
+#define __DEFINED_timer_t
+#endif
+
+#if defined(__NEED_clockid_t) && !defined(__DEFINED_clockid_t)
+typedef int clockid_t;
+#define __DEFINED_clockid_t
+#endif
+
+#if defined(__NEED_clock_t) && !defined(__DEFINED_clock_t)
+typedef long clock_t;
+#define __DEFINED_clock_t
+#endif
+
+#if defined(__NEED_struct_timeval) && !defined(__DEFINED_struct_timeval)
+struct timeval { time_t tv_sec; suseconds_t tv_usec; };
+#define __DEFINED_struct_timeval
+#endif
+
+#if defined(__NEED_struct_timespec) && !defined(__DEFINED_struct_timespec)
+struct timespec { time_t tv_sec; long tv_nsec; };
+#define __DEFINED_struct_timespec
+#endif
+
+
+#if defined(__NEED_pid_t) && !defined(__DEFINED_pid_t)
+typedef int pid_t;
+#define __DEFINED_pid_t
+#endif
+
+#if defined(__NEED_id_t) && !defined(__DEFINED_id_t)
+typedef unsigned id_t;
+#define __DEFINED_id_t
+#endif
+
+#if defined(__NEED_uid_t) && !defined(__DEFINED_uid_t)
+typedef unsigned uid_t;
+#define __DEFINED_uid_t
+#endif
+
+#if defined(__NEED_gid_t) && !defined(__DEFINED_gid_t)
+typedef unsigned gid_t;
+#define __DEFINED_gid_t
+#endif
+
+#if defined(__NEED_key_t) && !defined(__DEFINED_key_t)
+typedef int key_t;
+#define __DEFINED_key_t
+#endif
+
+#if defined(__NEED_useconds_t) && !defined(__DEFINED_useconds_t)
+typedef unsigned useconds_t;
+#define __DEFINED_useconds_t
+#endif
+
+
+#ifdef __cplusplus
+#if defined(__NEED_pthread_t) && !defined(__DEFINED_pthread_t)
+typedef unsigned long pthread_t;
+#define __DEFINED_pthread_t
+#endif
+
+#else
+#if defined(__NEED_pthread_t) && !defined(__DEFINED_pthread_t)
+typedef struct __pthread * pthread_t;
+#define __DEFINED_pthread_t
+#endif
+
+#endif
+#if defined(__NEED_pthread_once_t) && !defined(__DEFINED_pthread_once_t)
+typedef int pthread_once_t;
+#define __DEFINED_pthread_once_t
+#endif
+
+#if defined(__NEED_pthread_key_t) && !defined(__DEFINED_pthread_key_t)
+typedef unsigned pthread_key_t;
+#define __DEFINED_pthread_key_t
+#endif
+
+#if defined(__NEED_pthread_spinlock_t) && !defined(__DEFINED_pthread_spinlock_t)
+typedef int pthread_spinlock_t;
+#define __DEFINED_pthread_spinlock_t
+#endif
+
+#if defined(__NEED_pthread_mutexattr_t) && !defined(__DEFINED_pthread_mutexattr_t)
+typedef struct { unsigned __attr; } pthread_mutexattr_t;
+#define __DEFINED_pthread_mutexattr_t
+#endif
+
+#if defined(__NEED_pthread_condattr_t) && !defined(__DEFINED_pthread_condattr_t)
+typedef struct { unsigned __attr; } pthread_condattr_t;
+#define __DEFINED_pthread_condattr_t
+#endif
+
+#if defined(__NEED_pthread_barrierattr_t) && !defined(__DEFINED_pthread_barrierattr_t)
+typedef struct { unsigned __attr; } pthread_barrierattr_t;
+#define __DEFINED_pthread_barrierattr_t
+#endif
+
+#if defined(__NEED_pthread_rwlockattr_t) && !defined(__DEFINED_pthread_rwlockattr_t)
+typedef struct { unsigned __attr[2]; } pthread_rwlockattr_t;
+#define __DEFINED_pthread_rwlockattr_t
+#endif
+
+
+#if defined(__NEED_FILE) && !defined(__DEFINED_FILE)
+typedef struct _IO_FILE FILE;
+#define __DEFINED_FILE
+#endif
+
+
+#if defined(__NEED_mbstate_t) && !defined(__DEFINED_mbstate_t)
+typedef struct __mbstate_t { unsigned __opaque1, __opaque2; } mbstate_t;
+#define __DEFINED_mbstate_t
+#endif
+
+
+#if defined(__NEED_locale_t) && !defined(__DEFINED_locale_t)
+typedef struct __locale_struct * locale_t;
+#define __DEFINED_locale_t
+#endif
+
+
+#if defined(__NEED_sigset_t) && !defined(__DEFINED_sigset_t)
+typedef struct __sigset_t { unsigned long __bits[128/sizeof(long)]; } sigset_t;
+#define __DEFINED_sigset_t
+#endif
+
+
+#if defined(__NEED_struct_iovec) && !defined(__DEFINED_struct_iovec)
+struct iovec { void *iov_base; size_t iov_len; };
+#define __DEFINED_struct_iovec
+#endif
+
+
+#if defined(__NEED_socklen_t) && !defined(__DEFINED_socklen_t)
+typedef unsigned socklen_t;
+#define __DEFINED_socklen_t
+#endif
+
+#if defined(__NEED_sa_family_t) && !defined(__DEFINED_sa_family_t)
+typedef unsigned short sa_family_t;
+#define __DEFINED_sa_family_t
+#endif
+
+
+#undef _Addr
+#undef _Int64
+#undef _Reg