modules: fix build with -Wmissing-prototypes

Mainline commit 0fcb70851fbf ("Makefile.extrawarn: turn on
missing-prototypes globally") in 6.8-rc1 enables -Wmissing-prototypes
globally, revealing a lot of unclean code and also some actual problems.
This is also the case in vmmon and vmnet modules.

Most of them are addressed by making functions used only within one file
static. The missing prototype of random_get_entropy_fallback() is handled
by including <linux/timex.h> rather than <asm/timex.h>.

Finally, there are four functions in vmnet module which are actually used
in multiple files but instead of proper declarations, their prototype is
duplicated in vmnet-only/driver.c, risking that the two copies won't match
(which actually happened in one case). The cleanest solution would be
creating separate header files for them (bridge.h, netif.h, userif.h and
vnetUserListener.h) and including them in the respective source file and
driver.c. As the developers already handle similar cases by simply putting
the declarations into vnetInt.h, let us do the same to keep things simple.

vmmon-only/common/task.c

@@ -544,7 +544,7 @@ Task_Terminate(void)
  *-----------------------------------------------------------------------------
  */
 
-Selector
+static Selector
 TaskGetFlatWriteableDataSegment(void)
 {
    DTR hostGDTR;

vmmon-only/common/vmx86.c

@@ -49,7 +49,7 @@
 #include "x86svm.h"
 #include "x86cpuid_asm.h"
 #if defined(__linux__)
-#include <asm/timex.h>
+#include <linux/timex.h>
 #endif
 #include "perfctr.h"
 #include "x86vtinstr.h"
@@ -696,7 +696,7 @@ Vmx86FreeCrossPages(VMDriver *vm)
  *-----------------------------------------------------------------------------
  */
 
-void
+static void
 Vmx86FreeVMDriver(VMDriver *vm)
 {
    Vmx86_Free(vm->ptRootMpns);
@@ -729,7 +729,7 @@ Vmx86FreeVMDriver(VMDriver *vm)
  *-----------------------------------------------------------------------------
  */
 
-VMDriver *
+static VMDriver *
 Vmx86AllocVMDriver(uint32 numVCPUs)
 {
    VMDriver *vm = Vmx86_Calloc(1, sizeof *vm, TRUE);

vmmon-only/linux/driver.c

@@ -267,7 +267,7 @@ LinuxDriverInitTSCkHz(void)
  *----------------------------------------------------------------------
  */
 
-int
+static int
 LinuxDriverInit(void)
 {
    int retval;
@@ -335,7 +335,7 @@ LinuxDriverInit(void)
  *----------------------------------------------------------------------
  */
 
-void
+static void
 LinuxDriverExit(void)
 {
    /*

vmmon-only/linux/hostif.c

@@ -2923,7 +2923,7 @@ HostIF_CallOnEachCPU(void (*func)(void*), // IN: function to call
  *-----------------------------------------------------------------------------
  */
 
-Bool
+static Bool
 HostIFCheckTrackedMPN(VMDriver *vm, // IN: The VM instance
                       MPN mpn)      // IN: The MPN
 {
@@ -3043,7 +3043,7 @@ HostIF_ReadPhysical(VMDriver *vm,      // IN: The VM instance
  *----------------------------------------------------------------------
  */
 
-int
+static int
 HostIFWritePhysicalWork(MA ma,             // MA to be written to
                         VA64 addr,         // src data to write
                         Bool kernelBuffer, // is the buffer in kernel space?
@@ -3202,7 +3202,7 @@ HostIF_GetCurrentPCPU(void)
  *----------------------------------------------------------------------
  */
 
-int
+static int
 HostIFStartTimer(Bool rateChanged,  //IN: Did rate change?
                  unsigned int rate) //IN: current clock rate
 {

vmnet-only/bridge.c

@@ -1409,7 +1409,7 @@ VNetBridgeComputeHeaderPos(struct sk_buff *skb) // IN: buffer to examine
  *----------------------------------------------------------------------
  */
 
-void
+static void
 VNetBridgeSendLargePacket(struct sk_buff *skb,        // IN: packet to split
                           VNetBridge *bridge)         // IN: bridge
 {

vmnet-only/driver.c

@@ -50,18 +50,6 @@
 
 #include "vmnetInt.h"
 
-/*
- * Initialization and creation routines from other files.
- * Putting them here reduces the need for so many header files.
- */
-
-extern int VNetUserIf_Create(VNetPort **ret);
-extern int VNetNetIf_Create(char *devName, VNetPort **ret, int hubNum);
-extern int VNetBridge_Create(char *devName, uint32 flags, VNetJack *hubJack,
-                             VNetPort **ret);
-extern int VNetUserListener_Create(uint32 classMask, VNetJack *hubJack, VNetPort **ret);
-
-
 /*
  *  Structure for cycle detection of host interfaces.  This
  *  struct is only used by VNetCycleDetectIf().
@@ -295,7 +283,7 @@ VNetRemovePortFromList(const VNetPort *port) // IN: port to remove from list
  *----------------------------------------------------------------------
  */
 
-int
+static int
 vmnet_init_module(void)
 {
    int retval;
@@ -374,7 +362,7 @@ vmnet_init_module(void)
  *----------------------------------------------------------------------
  */
 
-void
+static void
 vmnet_cleanup_module(void)
 {
    unregister_chrdev(VNET_MAJOR_NUMBER, "vmnet");

vmnet-only/vnetInt.h

@@ -218,6 +218,13 @@ extern int VNetProc_Init(void);
 
 extern void VNetProc_Cleanup(void);
 
+int VNetNetIf_Create(char *devName, VNetPort **ret, int hubNum);
+int VNetUserIf_Create(VNetPort **ret);
+int VNetBridge_Create(const char *devName, uint32 flags, VNetJack *hubJack,
+		      VNetPort **ret);
+int VNetUserListener_Create(uint32 classMask, VNetJack *hubJack,
+			    VNetPort **port);
+
 
 /*
  *----------------------------------------------------------------------