Get Fabrice Bellard's JavaScript engine to build

$ m=tiny
$ make -j12 MODE=$m o/$m/third_party/quickjs/qjs.com
$ o/$m/third_party/quickjs/qjs.com -e 'console.log(2 + 2)'
4
$ ls -hal o/$m/third_party/quickjs/qjs.com
631.5K

See #97

third_party/gdtoa/gdtoa.internal.h

@@ -1,5 +1,6 @@
 #include "libc/math.h"
 #include "libc/mem/mem.h"
+#include "libc/runtime/fenv.h"
 #include "libc/str/str.h"
 #include "third_party/gdtoa/gdtoa.h"
 
@@ -10,11 +11,12 @@ Kudos go to Guy L. Steele, Jr. and Jon L. White\\n\
 Copyright (C) 1997, 1998, 2000 by Lucent Technologies\"");
 asm(".include \"libc/disclaimer.inc\"");
 
-#define IEEE_Arith 1
-#define IEEE_8087  1
-#define f_QNAN     0x7fc00000
-#define d_QNAN0    0x7ff80000
-#define d_QNAN1    0x0
+#define IEEE_Arith       1
+#define IEEE_8087        1
+#define Honor_FLT_ROUNDS 1
+#define f_QNAN           0x7fc00000
+#define d_QNAN0          0x7ff80000
+#define d_QNAN1          0x0
 
 /****************************************************************
 

third_party/gdtoa/gdtoa.mk

@@ -28,6 +28,7 @@ THIRD_PARTY_GDTOA_A_DIRECTDEPS =			\
 	LIBC_INTRIN					\
 	LIBC_MEM					\
 	LIBC_NEXGEN32E					\
+	LIBC_RUNTIME					\
 	LIBC_STR					\
 	LIBC_STUBS					\
 	LIBC_SYSV					\