Factorize common impl of process_execute()

Both implementations are the same. Move them to the common process.c.

app/src/sys/unix/process.c

@@ -153,11 +153,6 @@ process_execute_redirect(const char *const argv[], pid_t *pid, int *pipe_stdin,
     return res;
 }
 
-enum process_result
-process_execute(const char *const argv[], pid_t *pid) {
-    return process_execute_redirect(argv, pid, NULL, NULL, NULL);
-}
-
 bool
 process_terminate(pid_t pid) {
     if (pid <= 0) {

app/src/sys/win/process.c

@@ -142,11 +142,6 @@ error_close_stdin:
     return ret;
 }
 
-enum process_result
-process_execute(const char *const argv[], HANDLE *handle) {
-    return process_execute_redirect(argv, handle, NULL, NULL, NULL);
-}
-
 bool
 process_terminate(HANDLE handle) {
     return TerminateProcess(handle, 1);

app/src/util/process.c

@@ -3,6 +3,11 @@
 #include <libgen.h>
 #include "log.h"
 
+enum process_result
+process_execute(const char *const argv[], process_t *pid) {
+    return process_execute_redirect(argv, pid, NULL, NULL, NULL);
+}
+
 bool
 process_check_success(process_t proc, const char *name, bool close) {
     if (proc == PROCESS_NONE) {