diff --git a/compiler/main.v b/compiler/main.v
index 4dea930c40..1800fefefd 100644
--- a/compiler/main.v
+++ b/compiler/main.v
@@ -489,7 +489,7 @@ mut args := ''
 		a << '-lm -ldl -lpthread'
 	}
 	// Find clang executable
-	fast_clang := '/usr/local/Cellar/llvm/8.0.0/bin/clang'
+	fast_clang := 'ff'///usr/local/Cellar/llvm/8.0.0/bin/clang'
 	args := a.join(' ')
 	mut cmd := if os.file_exists(fast_clang) {
 		'$fast_clang $args'
diff --git a/vlib/os/os.v b/vlib/os/os.v
index 47e3afeafa..31dff20c00 100644
--- a/vlib/os/os.v
+++ b/vlib/os/os.v
@@ -5,12 +5,21 @@
 module os
 
 #include <sys/stat.h>
+#include <signal.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <errno.h>
+//#include <execinfo.h> // for backtrace_symbols_fd 
 
 const (
 	args = []string
 	MAX_PATH = 4096
 )
 
+const (
+	FILE_ATTRIBUTE_DIRECTORY = 16 // Windows 
+)
+
 struct FILE {
 }
 
@@ -490,3 +499,78 @@ pub fn getexepath() string {
 		return ''
 	}
 }
+
+pub fn is_dir(path string) bool {
+	$if windows {
+		val := int(C.GetFileAttributes(path.cstr()))
+		return val &FILE_ATTRIBUTE_DIRECTORY > 0
+	} 
+	$else { 
+		statbuf := C.stat{}
+		cstr := path.cstr()
+		if C.stat(cstr, &statbuf) != 0 {
+			return false
+		}
+		return statbuf.st_mode & S_IFMT == S_IFDIR
+	} 
+}
+
+fn chdir(path string) {
+	$if windows {
+		C._chdir(path.cstr())
+	}
+	$else { 
+		C.chdir(path.cstr())
+	} 
+}
+
+pub fn getwd() string {
+	buf := malloc(512)
+	$if windows {
+		if C._getcwd(buf, 512) == 0 {
+			return ''
+		}
+	}
+	$else { 
+		if C.getcwd(buf, 512) == 0 {
+			return ''
+		}
+	} 
+	return string(buf)
+}
+
+pub fn ls(path string) []string {
+	mut res := []string
+	dir := C.opendir(path.str)
+	if isnil(dir) {
+		println('ls() couldnt open dir "$path"')
+		print_c_errno()
+		return res
+	}
+	mut ent := &C.dirent{!}
+	for {
+		ent = C.readdir(dir)
+		if isnil(ent) {
+			break
+		}
+		name := tos_clone(ent.d_name)
+		if name != '.' && name != '..' && name != '' {
+			res << name
+		}
+	}
+	C.closedir(dir)
+	return res
+}
+
+fn log(s string) {
+}
+
+fn print_backtrace() {
+/* 
+	# void *buffer[100];
+	nptrs := 0
+	# nptrs = backtrace(buffer, 100);
+	# printf("%d!!\n", nptrs);
+	# backtrace_symbols_fd(buffer, nptrs, STDOUT_FILENO) ;
+*/ 
+}
diff --git a/vlib/os/os_mac.v b/vlib/os/os_mac.v
deleted file mode 100644
index b3990c688e..0000000000
--- a/vlib/os/os_mac.v
+++ /dev/null
@@ -1,70 +0,0 @@
-// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
-// Use of this source code is governed by an MIT license
-// that can be found in the LICENSE file.
-
-module os
-
-//#include <execinfo.h> // for backtrace_symbols_fd 
-#include <signal.h>
-#include <unistd.h>
-#include <dirent.h>
-#include <errno.h>
-// import darwin
-fn log(s string) {
-}
-
-
-pub fn is_dir(path string) bool {
-	statbuf := C.stat{}
-	cstr := path.cstr()
-	if C.stat(cstr, &statbuf) != 0 {
-		return false
-	}
-	return statbuf.st_mode & S_IFMT == S_IFDIR
-}
-
-fn chdir(path string) {
-	C.chdir(path.cstr())
-}
-
-pub fn getwd() string {
-	cwd := malloc(512)
-	if C.getcwd(cwd, 512) == 0 {
-		return ''
-	}
-	return string(cwd)
-}
-
-pub fn ls(path string) []string {
-	mut res := []string
-	dir := C.opendir(path.str)
-	if isnil(dir) {
-		println('ls() couldnt open dir "$path"')
-		print_c_errno()
-		return res
-	}
-	mut ent := &C.dirent{!}
-	for {
-		ent = C.readdir(dir)
-		if isnil(ent) {
-			break
-		}
-		name := tos_clone(ent.d_name)
-		if name != '.' && name != '..' && name != '' {
-			res << name
-		}
-	}
-	C.closedir(dir)
-	return res
-}
-
-fn print_backtrace() {
-/* 
-	# void *buffer[100];
-	nptrs := 0
-	# nptrs = backtrace(buffer, 100);
-	# printf("%d!!\n", nptrs);
-	# backtrace_symbols_fd(buffer, nptrs, STDOUT_FILENO) ;
-*/ 
-}
-
diff --git a/vlib/os/os_win.v b/vlib/os/os_win.v
deleted file mode 100644
index bbb18861c9..0000000000
--- a/vlib/os/os_win.v
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
-// Use of this source code is governed by an MIT license
-// that can be found in the LICENSE file.
-
-module os
-
-pub fn ls(path string) []string {
-	mut res := []string
-	return res
-}
-
-pub fn getwd() string {
-	mut buffer := malloc(512)
-	
-	buffer = C._getcwd(0, 0)
-	// A NULL return value indicates an error
-	if isnil(buffer) {
-		return ''
-	}
-	return string(buffer)
-}
-
-const (
-	FILE_ATTRIBUTE_DIRECTORY = 16
-)
-
-fn is_dir(path string) bool {
-	val := int(C.GetFileAttributes(path.cstr()))
-	return val &FILE_ATTRIBUTE_DIRECTORY > 0
-}
-
-fn chdir(path string) {
-	C._chdir(path.cstr())
-}
-
-fn log(s string) {
-}
-