add libc wrapper

Signed-off-by: leongross <[email protected]>

Author: leongross

GNUmakefile

@@ -926,6 +926,7 @@ endif
 	@cp -rp lib/musl/src/env             build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/errno           build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/exit            build/release/tinygo/lib/musl/src
+	@cp -rp lib/musl/src/fcntl           build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/include         build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/internal        build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/legacy          build/release/tinygo/lib/musl/src

builder/musl.go

@@ -116,6 +116,7 @@ var libMusl = Library{
 			"env/*.c",
 			"errno/*.c",
 			"exit/*.c",
+			"fcntl/*.c",
 			"internal/defsysinfo.c",
 			"internal/libc.c",
 			"internal/syscall_ret.c",

src/runtime/os_linux.go

@@ -139,3 +139,12 @@ func hardwareRand() (n uint64, ok bool) {
 //
 //export getrandom
 func libc_getrandom(buf unsafe.Pointer, buflen uintptr, flags uint32) uint32
+
+// int fcntl(int fd, int cmd, int arg);
+//
+// export fcntl
+func libc_fcntl(fd int, cmd int, arg int) (ret int)
+
+func fcntl(fd int, cmd int, arg int) int {
+	return libc_fcntl(fd, cmd, arg)
+}