Renamed all the sources to start with "physfs_"

So now you can drop this into your program and not worry about filename
conflicts, or where "platform_unix.c" came from in the debugger, etc.

Also renamed the "beos" sources to "haiku" and "macosx" to "macos" to match
modern platform names.

CMakeLists.txt

@@ -42,7 +42,7 @@ endif()
 if(HAIKU)
     # We add this explicitly, since we don't want CMake to think this
     #  is a C++ project unless we're on Haiku.
-    set(PHYSFS_HAIKU_SRCS src/platform_beos.cpp)
+    set(PHYSFS_HAIKU_SRCS src/physfs_platform_haiku.cpp)
     find_library(BE_LIBRARY be)
     find_library(ROOT_LIBRARY root)
     set(OPTIONAL_LIBRARY_LIBS ${OPTIONAL_LIBRARY_LIBS} ${BE_LIBRARY} ${ROOT_LIBRARY})
@@ -63,23 +63,23 @@ set(PHYSFS_SRCS
     src/physfs.c
     src/physfs_byteorder.c
     src/physfs_unicode.c
-    src/platform_posix.c
-    src/platform_unix.c
-    src/platform_macosx.c
-    src/platform_windows.c
-    src/platform_os2.c
-    src/archiver_dir.c
-    src/archiver_unpacked.c
-    src/archiver_grp.c
-    src/archiver_hog.c
-    src/archiver_7z.c
-    src/archiver_mvl.c
-    src/archiver_qpak.c
-    src/archiver_wad.c
-    src/archiver_zip.c
-    src/archiver_slb.c
-    src/archiver_iso9660.c
-    src/archiver_vdf.c
+    src/physfs_platform_posix.c
+    src/physfs_platform_unix.c
+    src/physfs_platform_macos.c
+    src/physfs_platform_windows.c
+    src/physfs_platform_os2.c
+    src/physfs_archiver_dir.c
+    src/physfs_archiver_unpacked.c
+    src/physfs_archiver_grp.c
+    src/physfs_archiver_hog.c
+    src/physfs_archiver_7z.c
+    src/physfs_archiver_mvl.c
+    src/physfs_archiver_qpak.c
+    src/physfs_archiver_wad.c
+    src/physfs_archiver_zip.c
+    src/physfs_archiver_slb.c
+    src/physfs_archiver_iso9660.c
+    src/physfs_archiver_vdf.c
     ${PHYSFS_HAIKU_SRCS}
 )