diff --git a/compiler/main.v b/compiler/main.v
index 6a9f8d4726..97add2044e 100644
--- a/compiler/main.v
+++ b/compiler/main.v
@@ -25,7 +25,7 @@ enum BuildMode {
 }
 
 fn vtmp_path() string {
-	return os.home_dir() + '/.vlang$Version/'
+	return os.home_dir() + '/.vlang/'
 }
 
 const (
@@ -159,19 +159,6 @@ fn (c mut V) compile() {
 	}
 	// Main pass
 	cgen.run = RUN_MAIN
-	if c.os == MAC {
-		cgen.genln('#define mac (1) ')
-		// cgen.genln('#include <pthread.h>')
-	}
-	if c.os == LINUX {
-		cgen.genln('#define linux (1) ')
-		cgen.genln('#include <pthread.h>')
-	}
-	if c.os == WINDOWS {
-		cgen.genln('#define windows (1) ')
-		// cgen.genln('#include <WinSock2.h>')
-		cgen.genln('#include <windows.h> ')
-	}
 	if c.is_play {
 		cgen.genln('#define VPLAY (1) ')
 	}
@@ -182,6 +169,22 @@ fn (c mut V) compile() {
 #include <stdarg.h> // for va_list 
 #include <inttypes.h>  // int64_t etc 
 
+
+#ifdef __linux__ 
+#include <pthread.h> 
+#endif 
+
+
+#ifdef __APPLE__ 
+
+#endif 
+
+
+#ifdef _WIN32 
+#include <windows.h>
+//#include <WinSock2.h> 
+#endif 
+
 //================================== TYPEDEFS ================================*/ 
 
 typedef unsigned char byte;
diff --git a/compiler/parser.v b/compiler/parser.v
index fa9924f05c..6d9011cc5a 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -2494,6 +2494,16 @@ fn (p mut Parser) get_tmp_counter() int {
 	return p.tmp_cnt
 }
 
+fn os_name_to_ifdef(name string) string { 
+	switch name {
+		case 'windows': return '_WIN32'
+		case 'mac': return '__APPLE__'
+		case 'linux': return '__linux__' 
+	} 
+	panic('bad os ifdef name "$name"') 
+	return '' 
+} 
+
 fn (p mut Parser) comp_time() {
 	p.next()
 	if p.tok == IF {
@@ -2504,11 +2514,12 @@ fn (p mut Parser) comp_time() {
 		}
 		name := p.check_name()
 		if name in SupportedPlatforms {
+			ifdef_name := os_name_to_ifdef(name) 
 			if not {
-				p.genln('#ifndef $name')
+				p.genln('#ifndef $ifdef_name')
 			}
 			else {
-				p.genln('#ifdef $name')
+				p.genln('#ifdef $ifdef_name')
 			}
 			p.check(LCBR)
 			p.statements_no_curly_end()
diff --git a/gg/gg.v b/gg/gg.v
index 788ede3c5f..ccd9d6f21b 100644
--- a/gg/gg.v
+++ b/gg/gg.v
@@ -239,9 +239,9 @@ fn (ctx &GG) draw_rect2(x, y, w, h float, c gx.Color) {
 	ctx.shader.set_int('has_texture', 0)
 	// 4--1
 	// 3--2
-#ifdef linux
+	$if linux { 
 	// y += h
-#endif
+	} 
 	vertices := [
 	x + w, y, 0,
 	x + w, y + h, 0,
diff --git a/os/os.v b/os/os.v
index 8d0d77b5aa..e4dfa7fb01 100644
--- a/os/os.v
+++ b/os/os.v
@@ -288,15 +288,15 @@ pub fn system(cmd string) string {
 fn system_into_lines(s string) []string {
 	mut res := []string
 	cmd := '$s 2>&1'
-#ifdef windows
-	# FILE* f = _popen(cmd.str, "r");
-#else
-	# FILE* f = popen(cmd.str, "r");
-#endif
-	#define MAX 5000
-	// # char buf[MAX];
-	# char * buf = malloc(sizeof(char) * MAX);
-	# while (fgets(buf, MAX, f) != NULL)
+	max := 5000 
+	$if windows { 
+		# FILE* f = _popen(cmd.str, "r");
+	}
+	$else { 
+		# FILE* f = popen(cmd.str, "r");
+	} 
+	# char * buf = malloc(sizeof(char) * max);
+	# while (fgets(buf, max, f) != NULL)
 	{
 		val := ''
 		# buf[strlen(buf) - 1] = '\0'; // eat the newline fgets() stores
@@ -323,11 +323,12 @@ fn exit(code int) {
 pub fn file_exists(path string) bool {
 	// # return access( path.str, F_OK ) != -1 ;
 	res := false
-#ifdef windows
-	# res = _access( path.str, 0 ) != -1 ;
-#else
-	# res = access( path.str, 0 ) != -1 ;
-#endif
+	$if windows { 
+		# res = _access( path.str, 0 ) != -1 ;
+	}
+	$else { 
+		# res = access( path.str, 0 ) != -1 ;
+	} 
 	return res
 }
 
@@ -435,16 +436,16 @@ pub fn write_file(path, text string) {
 }
 
 fn on_segfault(f voidptr) {
-#ifdef windows
-	return
-#endif
-#ifdef mac
-	# struct sigaction sa;
-	# memset(&sa, 0, sizeof(struct sigaction));
-	# sigemptyset(&sa.sa_mask);
-	# sa.sa_sigaction = f;
-	# sa.sa_flags   = SA_SIGINFO;
-	# sigaction(SIGSEGV, &sa, 0);
-#endif
+	$if windows { 
+		return
+	} 
+	$if mac { 
+		# struct sigaction sa;
+		# memset(&sa, 0, sizeof(struct sigaction));
+		# sigemptyset(&sa.sa_mask);
+		# sa.sa_sigaction = f;
+		# sa.sa_flags   = SA_SIGINFO;
+		# sigaction(SIGSEGV, &sa, 0);
+	} 
 }