libc: implement common abs for various integer sizes

Author: kada49

lib/c.zig

@@ -16,6 +16,7 @@ else
 comptime {
     if (builtin.target.isMuslLibC() or builtin.target.isWasiLibC()) {
         // Files specific to musl and wasi-libc.
+        _ = @import("c/stdlib.zig");
         _ = @import("c/string.zig");
         _ = @import("c/strings.zig");
     }

lib/c/stdlib.zig

@@ -0,0 +1,29 @@
+const std = @import("std");
+const common = @import("common.zig");
+const c = @cImport({
+    @cInclude("stdint.h");
+});
+const c_intmax_t = c.intmax_t;
+
+comptime {
+    @export(&abs, .{ .name = "abs", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&imaxabs, .{ .name = "imaxabs", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&labs, .{ .name = "labs", .linkage = common.linkage, .visibility = common.visibility });
+    @export(&llabs, .{ .name = "llabs", .linkage = common.linkage, .visibility = common.visibility });
+}
+
+fn abs(a: c_int) callconv(.c) c_int {
+    return if (a > 0) a else -a;
+}
+
+fn imaxabs(a: c_intmax_t) callconv(.c) c_intmax_t {
+    return if (a > 0) a else -a;
+}
+
+fn labs(a: c_long) callconv(.c) c_long {
+    return if (a > 0) a else -a;
+}
+
+fn llabs(a: c_longlong) callconv(.c) c_longlong {
+    return if (a > 0) a else -a;
+}

lib/libc/musl/src/stdlib/abs.c

@@ -1814,7 +1814,6 @@ const src_files = [_][]const u8{
     "musl/src/stdio/vwscanf.c",
     "musl/src/stdio/wprintf.c",
     "musl/src/stdio/wscanf.c",
-    "musl/src/stdlib/abs.c",
     "musl/src/stdlib/atof.c",
     "musl/src/stdlib/atoi.c",
     "musl/src/stdlib/atol.c",
@@ -1824,11 +1823,8 @@ const src_files = [_][]const u8{
     "musl/src/stdlib/ecvt.c",
     "musl/src/stdlib/fcvt.c",
     "musl/src/stdlib/gcvt.c",
-    "musl/src/stdlib/imaxabs.c",
     "musl/src/stdlib/imaxdiv.c",
-    "musl/src/stdlib/labs.c",
     "musl/src/stdlib/ldiv.c",
-    "musl/src/stdlib/llabs.c",
     "musl/src/stdlib/lldiv.c",
     "musl/src/stdlib/qsort.c",
     "musl/src/stdlib/qsort_nr.c",

lib/libc/musl/src/stdlib/imaxabs.c

@@ -1024,7 +1024,6 @@ const libc_top_half_src_files = [_][]const u8{
     "musl/src/stdio/vwscanf.c",
     "musl/src/stdio/wprintf.c",
     "musl/src/stdio/wscanf.c",
-    "musl/src/stdlib/abs.c",
     "musl/src/stdlib/atof.c",
     "musl/src/stdlib/atoi.c",
     "musl/src/stdlib/atol.c",
@@ -1034,11 +1033,8 @@ const libc_top_half_src_files = [_][]const u8{
     "musl/src/stdlib/ecvt.c",
     "musl/src/stdlib/fcvt.c",
     "musl/src/stdlib/gcvt.c",
-    "musl/src/stdlib/imaxabs.c",
     "musl/src/stdlib/imaxdiv.c",
-    "musl/src/stdlib/labs.c",
     "musl/src/stdlib/ldiv.c",
-    "musl/src/stdlib/llabs.c",
     "musl/src/stdlib/lldiv.c",
     "musl/src/stdlib/qsort.c",
     "musl/src/stdlib/qsort_nr.c",