Move drives.h to common include dir

Judging by the usage, this header belongs in there instead of being
limited to dos module only.  This change makes it easier to reuse code
for new features related to drives mounting/unmounting.

include/Makefile.am

@@ -11,6 +11,7 @@ dma.h \
 dosbox.h \
 dos_inc.h \
 dos_system.h \
+drives.h \
 fpu.h \
 hardware.h \
 inout.h \

src/dos/Makefile.am

@@ -4,7 +4,7 @@ noinst_LIBRARIES = libdos.a
 EXTRA_DIST = dos_codepages.h dos_keyboard_layout_data.h
 libdos_a_SOURCES = dos.cpp dos_devices.cpp dos_execute.cpp dos_files.cpp dos_ioctl.cpp dos_memory.cpp \
                    dos_misc.cpp dos_classes.cpp dos_programs.cpp dos_tables.cpp \
-		   drives.cpp drives.h drive_virtual.cpp drive_local.cpp drive_cache.cpp drive_fat.cpp \
+		   drives.cpp drive_virtual.cpp drive_local.cpp drive_cache.cpp drive_fat.cpp \
 		   drive_iso.cpp dev_con.h dos_mscdex.cpp dos_keyboard_layout.cpp \
 		   cdrom.h cdrom.cpp cdrom_image.cpp \
 		   drive_overlay.cpp

src/ints/bios_disk.cpp

@@ -27,7 +27,7 @@
 #include "regs.h"
 #include "mem.h"
 #include "dos_inc.h" /* for Drives[] */
-#include "../dos/drives.h"
+#include "drives.h"
 #include "mapper.h"
 
 diskGeo DiskGeometryList[] = {

src/shell/shell_cmds.cpp

@@ -30,7 +30,7 @@
 #include "callback.h"
 #include "regs.h"
 #include "bios.h"
-#include "../dos/drives.h"
+#include "drives.h"
 #include "support.h"
 #include "control.h"
 

vs/dosbox.vcxproj

@@ -277,6 +277,7 @@
     <ClInclude Include="..\include\dosbox.h" />
     <ClInclude Include="..\include\dos_inc.h" />
     <ClInclude Include="..\include\dos_system.h" />
+    <ClInclude Include="..\include\drives.h" />
     <ClInclude Include="..\include\fpu.h" />
     <ClInclude Include="..\include\hardware.h" />
     <ClInclude Include="..\include\inout.h" />
@@ -339,7 +340,6 @@
     <ClInclude Include="..\src\dos\cdrom.h" />
     <ClInclude Include="..\src\dos\dev_con.h" />
     <ClInclude Include="..\src\dos\dos_mscdex.h" />
-    <ClInclude Include="..\src\dos\drives.h" />
     <ClInclude Include="..\src\dos\Ntddcdrm.h" />
     <ClInclude Include="..\src\dos\Ntddscsi.h" />
     <ClInclude Include="..\src\dos\Ntddstor.h" />