Rename fs*.c -> os*.c

I planned to put just the file system routines into these files, but
there are starting to be so many of them that I don't want to
duplicate the same set for networking, subprocesses etc.

c/builtins.c

@@ -27,7 +27,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/env_unix.c

@@ -26,7 +26,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/equalhash.c

@@ -18,7 +18,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/flisp.c

@@ -55,7 +55,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/flmain.c

@@ -17,7 +17,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/iostream.c

@@ -19,7 +19,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/libraries.c

@@ -27,7 +27,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/os_darwin.c

@@ -1,6 +1,6 @@
 #include <mach-o/dyld.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_dragonfly.c

@@ -2,7 +2,7 @@
 
 #include <sys/sysctl.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_freebsd.c

@@ -2,7 +2,7 @@
 
 #include <sys/sysctl.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_haiku.c

@@ -1,6 +1,6 @@
 #include <unistd.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_linux.c

@@ -2,7 +2,7 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_minix.c

@@ -1,6 +1,6 @@
 #include <unistd.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_netbsd.c

@@ -2,7 +2,7 @@
 
 #include <sys/sysctl.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_openbsd.c

@@ -10,7 +10,7 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_sunos.c

@@ -1,6 +1,6 @@
 #include <unistd.h>
 
-#include "fs.h"
+#include "os.h"
 
 char *get_exename(char *buf, size_t size)
 {

c/os_unix.c

@@ -1,7 +1,7 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "fs.h"
+#include "os.h"
 
 void path_to_dirname(char *path)
 {

c/os_windows.c

@@ -1,6 +1,6 @@
 #include <windows.h>
 
-#include "fs.h"
+#include "os.h"
 
 void path_to_dirname(char *path)
 {

c/string.c

@@ -28,7 +28,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

c/table.c

@@ -19,7 +19,7 @@
 #include "htable.h"
 #include "htableh_inc.h"
 #include "bitvector.h"
-#include "fs.h"
+#include "os.h"
 #include "random.h"
 #include "llt.h"
 

scripts/build.sh

@@ -11,8 +11,8 @@ o_files="$o_files env_unix.o"
 o_files="$o_files equalhash.o"
 o_files="$o_files flisp.o"
 o_files="$o_files flmain.o"
-o_files="$o_files fs_$os.o"
-o_files="$o_files fs_unix.o"
+o_files="$o_files os_$os.o"
+o_files="$o_files os_unix.o"
 o_files="$o_files hashing.o"
 o_files="$o_files htable.o"
 o_files="$o_files int2str.o"
@@ -89,8 +89,8 @@ $CC $CFLAGS -c ../c/dump.c
 $CC $CFLAGS -c ../c/env_unix.c
 $CC $CFLAGS -c ../c/equalhash.c
 $CC $CFLAGS -c ../c/flisp.c
-$CC $CFLAGS -c ../c/fs_"$os".c
-$CC $CFLAGS -c ../c/fs_unix.c
+$CC $CFLAGS -c ../c/os_"$os".c
+$CC $CFLAGS -c ../c/os_unix.c
 $CC $CFLAGS -c ../c/hashing.c
 $CC $CFLAGS -c ../c/htable.c
 $CC $CFLAGS -c ../c/int2str.c