diff --git a/Common/Std/libc.c b/Common/Std/libc.c
index eef4f5e..6ad1dd7 100644
--- a/Common/Std/libc.c
+++ b/Common/Std/libc.c
@@ -28,14 +28,14 @@ com_std_fd com_std_open(char const *path, uint32_t flags) {
 }
 
 bool com_std_write(com_std_fd fd, void const *data, uint32_t bytes) {
-  com_std_assert(fd != NULL && data != NULL && bytes != 0);
+  com_std_assert(data != NULL && bytes != 0);
   bool s = fwrite(data, 1, bytes, fd) == bytes;
   fflush(fd);
   return s;
 }
 
 int32_t com_std_read(com_std_fd fd, void *data, uint32_t upto) {
-  com_std_assert(fd != NULL && data != NULL && upto != 0);
+  com_std_assert(data != NULL && upto != 0);
   return fread(data, 1, upto, fd);
 }
 
diff --git a/Common/std.h b/Common/std.h
index 35456bf..938e73e 100644
--- a/Common/std.h
+++ b/Common/std.h
@@ -10,9 +10,9 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#if COM_DEF_TARGET == COM_DEF_TARGET_WASM
-#define COM_STD_INFD 0
-#define COM_STD_OUTFD 1
+#if COM_DEF_TARGET != COM_DEF_TARGET_COSMO
+#define COM_STD_INFD (void *)0
+#define COM_STD_OUTFD (void *)1
 #else
 /* TODO: Make it more graceful, probably with static func. */
 #include <unistd.h>
diff --git a/Player/Display/x11.c b/Player/Display/x11.c
index fa0e373..5b1d876 100644
--- a/Player/Display/x11.c
+++ b/Player/Display/x11.c
@@ -408,6 +408,10 @@ static bool plr_x11_establish_connection(com_std_fd xfd, int argc,
                                          char const *const *argv) {
   com_buf_make_on_stack(char, xauthbuf, 1024, 0);
 
+/* TODO: Genralize inside std? */
+#if COM_DEF_TARGET == COM_DEF_TARGET_COSMO
+  char const *xauthpath = getenv("XAUTHORITY");
+#else
   /* First we need to authenticate X11 connection, which requires some funk.
    */
   /* We assume that $XAUTHORITY is set and I hope it is true. */
@@ -419,10 +423,11 @@ static bool plr_x11_establish_connection(com_std_fd xfd, int argc,
       break;
     }
   }
+#endif
 
   /* Open it and parse. */
   com_std_fd const xauthfd = com_std_open(xauthpath, COM_STD_OPEN_READ);
-  if (xauthfd < 0) {
+  if (!xauthfd) {
     com_std_print('c', "Failure to initialize X11");
     return false;
   }
@@ -481,8 +486,9 @@ extern int plr_display_x11_main(int argc, char const *const *argv) {
   // com_vec_t v0 = com_mat_vec_project(com_mat_reoder(m0), com_vec_identity());
   // com_fix_print(v0.a[0]);
 
+/* TODO: Move to separate executable maybe? */
 #ifndef NDEBUG
-  com_test_run();
+  // com_test_run();
 #endif
 
   // com_fix_run_tests();
diff --git a/Player/Main/cosmo.c b/Player/Main/cosmo.c
index 41b0547..9950bf6 100644
--- a/Player/Main/cosmo.c
+++ b/Player/Main/cosmo.c
@@ -1,7 +1,5 @@
-#include "../../Common/std.h"
 #include "../Display/display.h"
-#include <stdio.h>
+
 extern int main(int argc, char const *const *argv) {
-  com_std_write(COM_STD_OUTFD, "TEST?", sizeof "TEST?" - 1);
   return plr_display_x11_main(argc, argv);
 }
diff --git a/Player/Makefile b/Player/Makefile
index 19b2eae..ea292f8 100644
--- a/Player/Makefile
+++ b/Player/Makefile
@@ -8,6 +8,11 @@ RUN 	?= 0
 ISCLANG = 1
 ifeq ($(MAKECMDGOALS),cosmo)
 	ISCLANG = 0
+	ifeq ($(DEBUG), 1)
+	    CFLAGS += -mdbg
+	else
+	    CFLAGS += -mtiny
+	endif
 endif
 CFLAGS = -Wall -std=gnu99 -ffast-math -fno-ident -fvisibility=hidden
 ifeq ($(ISCLANG), 1)
@@ -40,13 +45,15 @@ endif
 ifeq ($(DEBUG), 1)
     CFLAGS += -g3
 else
-    CFLAGS += -DNDEBUG -Wl,--strip-all
+    CFLAGS += -DNDEBUG -s
 endif
 ifeq ($(RELEASE), 1)
     CFLAGS += -O3 -fmerge-all-constants -Wl,-O3 \
-    		  -ffunction-sections -fdata-sections -Wl,--gc-sections \
-    		  -Wl,-mllvm,--vectorize-slp=true \
-    		  -Wl,-mllvm,--enable-gvn-hoist=true
+    		  -ffunction-sections -fdata-sections -Wl,--gc-sections
+	ifeq ($(ISCLANG), 1)
+		CFLAGS += -Wl,-mllvm,--vectorize-slp=true \
+    		  	  -Wl,-mllvm,--enable-gvn-hoist=true
+	endif
 endif
 
 linux: CFLAGS += -static -mbmi2 -nostdlib
@@ -59,9 +66,10 @@ wasm:
 	$(CC) -o player.wasm ./amalgam.c $(CFLAGS)
 
 # todo: Add -mtiny for release without debug
-cosmo: CC = ./Cosmo/bin/cosmocc -I /usr/include/X11 -mdbg
+cosmo: CC = ./Cosmo/bin/cosmocc
+cosmo: CFLAGS += -I /usr/include/X11 -mclang
 cosmo: ./amalgam.c
-	$(CC) -o ./Out/Cosmo/player $^
+	$(CC) $(CFLAGS) -o ./Out/Cosmo/player $^
 ifeq ($(RUN), 1)
 ifeq ($(DEBUG), 1)
 	gdb ./Out/Cosmo/player.com.dbg