Fix -Wmissing-declarations and -Wmissing-prototypes warnings

This is a theoretical ABI change, but hopefully no third-party app is
linking against undocumented functions not part of any header file.
Also remove an unused function.

(cherry picked from commit 188b608)

qrexec-lib/Makefile

@@ -1,5 +1,5 @@
 CC=gcc
-CFLAGS := $(CFLAGS) -I. -g3 -O2 -Wall -Wextra -Werror -pie -fPIC
+CFLAGS := $(CFLAGS) -I. -g3 -O2 -Wall -Wextra -Werror -pie -fPIC -Wmissing-declarations -Wmissing-prototypes
 SO_VER=2
 LDFLAGS+=-Wl,--no-undefined,--as-needed,-Bsymbolic -L .
 .PHONY: all clean install check

qrexec-lib/crc32.c

@@ -29,46 +29,6 @@
 unsigned long Crc32_ComputeBuf( unsigned long inCrc32, const void *buf,
                                        size_t bufLen );
 
-/*----------------------------------------------------------------------------*\
- *  NAME:
- *     Crc32_ComputeFile() - compute CRC-32 value for a file
- *  DESCRIPTION:
- *     Computes the CRC-32 value for an opened file.
- *  ARGUMENTS:
- *     file - file pointer
- *     outCrc32 - (out) result CRC-32 value
- *  RETURNS:
- *     err - 0 on success or -1 on error
- *  ERRORS:
- *     - file errors
-\*----------------------------------------------------------------------------*/
-
-int Crc32_ComputeFile( FILE *file, unsigned long *outCrc32 )
-{
-#   define CRC_BUFFER_SIZE  8192
-    unsigned char buf[CRC_BUFFER_SIZE];
-    size_t bufLen;
-
-    /** accumulate crc32 from file **/
-    *outCrc32 = 0;
-    while (1) {
-        bufLen = fread( buf, 1, CRC_BUFFER_SIZE, file );
-        if (bufLen == 0) {
-            if (ferror(file)) {
-                fprintf( stderr, "error reading file\n" );
-                goto ERR_EXIT;
-            }
-            break;
-        }
-        *outCrc32 = Crc32_ComputeBuf( *outCrc32, buf, bufLen );
-    }
-    return( 0 );
-
-    /** error exit **/
-ERR_EXIT:
-    return( -1 );
-}
-
 /*----------------------------------------------------------------------------*\
  *  NAME:
  *     Crc32_ComputeBuf() - computes the CRC-32 value of a memory buffer

qrexec-lib/ioall.c

@@ -24,8 +24,9 @@
 #include <stdlib.h>
 #include <fcntl.h>
 #include <errno.h>
+#include "libqubes-rpc-filecopy.h"
 
-void perror_wrapper(const char * msg)
+static void perror_wrapper(const char * msg)
 {
     int prev=errno;
     perror(msg);

qrexec-lib/unpack.c

@@ -45,7 +45,7 @@ void send_status_and_crc(int code, const char *last_filename);
 #define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT)
 #endif
 
-_Noreturn void do_exit(int code, const char *last_filename)
+static _Noreturn void do_exit(int code, const char *last_filename)
 {
     close(0);
     send_status_and_crc(code, last_filename);
@@ -74,7 +74,7 @@ void set_procfs_fd(int value)
     use_tmpfile = 1;
 }
 
-int wait_for_space(int fd, unsigned long how_much) {
+static int wait_for_space(int fd, unsigned long how_much) {
     int counter = 0;
     struct statvfs fs_space;
     do {
@@ -91,7 +91,7 @@ int wait_for_space(int fd, unsigned long how_much) {
 }
 
 static unsigned long crc32_sum = 0;
-int read_all_with_crc(int fd, void *buf, int size) {
+static int read_all_with_crc(int fd, void *buf, int size) {
     int ret;
     ret = read_all(fd, buf, size);
     if (ret)
@@ -196,8 +196,8 @@ static int opendir_safe(int dirfd, char *path, const char **last_segment)
     }
 }
 
-void process_one_file_reg(struct file_header *untrusted_hdr,
-        const char *untrusted_name)
+static void process_one_file_reg(struct file_header *untrusted_hdr,
+                                 const char *untrusted_name)
 {
     int ret;
     int fdout = -1, safe_dirfd;
@@ -260,8 +260,8 @@ void process_one_file_reg(struct file_header *untrusted_hdr,
 }
 
 
-void process_one_file_dir(struct file_header *untrusted_hdr,
-        const char *untrusted_name)
+static void process_one_file_dir(struct file_header *untrusted_hdr,
+                                 const char *untrusted_name)
 {
     int safe_dirfd;
     const char *last_segment;
@@ -291,8 +291,8 @@ void process_one_file_dir(struct file_header *untrusted_hdr,
     free(path_dup);
 }
 
-void process_one_file_link(struct file_header *untrusted_hdr,
-        const char *untrusted_name)
+static void process_one_file_link(struct file_header *untrusted_hdr,
+                                  const char *untrusted_name)
 {
     char untrusted_content[MAX_PATH_LENGTH];
     const char *last_segment;
@@ -331,7 +331,7 @@ void process_one_file_link(struct file_header *untrusted_hdr,
     free(path_dup);
 }
 
-void process_one_file(struct file_header *untrusted_hdr, int flags)
+static void process_one_file(struct file_header *untrusted_hdr, int flags)
 {
     unsigned int namelen;
     if (untrusted_hdr->namelen > MAX_PATH_LENGTH - 1)