Fold conv package into fmt

Both packages had nearly identical dependency requirements, so merging
them should help reduce the complexity of the build graph.

third_party/stb/stb.mk

@@ -28,18 +28,17 @@ THIRD_PARTY_STB_A_OBJS =				\
 THIRD_PARTY_STB_A_DIRECTDEPS =				\
 	DSP_CORE					\
 	LIBC_ALG					\
-	LIBC_FMT					\
-	LIBC_STDIO					\
 	LIBC_BITS					\
-	LIBC_CONV					\
+	LIBC_FMT					\
+	LIBC_LOG					\
 	LIBC_MEM					\
 	LIBC_NEXGEN32E					\
-	LIBC_TINYMATH					\
 	LIBC_RUNTIME					\
+	LIBC_STDIO					\
 	LIBC_STR					\
-	LIBC_LOG					\
-	LIBC_X						\
 	LIBC_STUBS					\
+	LIBC_TINYMATH					\
+	LIBC_X						\
 	THIRD_PARTY_ZLIB
 
 THIRD_PARTY_STB_A_DEPS :=				\

third_party/stb/stb_image.c

@@ -20,7 +20,7 @@
 #include "libc/assert.h"
 #include "libc/bits/bits.h"
 #include "libc/calls/calls.h"
-#include "libc/conv/conv.h"
+#include "libc/fmt/conv.h"
 #include "libc/limits.h"
 #include "libc/log/gdb.h"
 #include "libc/log/log.h"

third_party/stb/stb_image_write.c

@@ -120,7 +120,7 @@
  */
 #include "dsp/core/core.h"
 #include "libc/assert.h"
-#include "libc/conv/conv.h"
+#include "libc/fmt/conv.h"
 #include "libc/fmt/fmt.h"
 #include "libc/limits.h"
 #include "libc/macros.h"

third_party/stb/stb_image_write_png.c

@@ -119,7 +119,7 @@
  *   Public Domain (www.unlicense.org)
  */
 #include "libc/assert.h"
-#include "libc/conv/conv.h"
+#include "libc/fmt/conv.h"
 #include "libc/limits.h"
 #include "libc/mem/mem.h"
 #include "libc/stdio/stdio.h"

third_party/stb/stb_vorbis.c

@@ -36,7 +36,7 @@
 #include "libc/assert.h"
 #include "libc/bits/bits.h"
 #include "libc/calls/calls.h"
-#include "libc/conv/conv.h"
+#include "libc/fmt/conv.h"
 #include "libc/limits.h"
 #include "libc/math.h"
 #include "libc/mem/alloca.h"