run-command: make exists_in_PATH() non-static

Remove the `static` keyword from `exists_in_PATH()` function
and declare the function in `run-command.h` file.
The function will be used in bisect_visualize() in a later
commit.

Mentored by: Christian Couder <[email protected]>
Mentored by: Johannes Schindelin <[email protected]>
Signed-off-by: Tanushree Tumane <[email protected]>
Signed-off-by: Miriam Rubio <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pranitbauva1997

run-command.c

@@ -210,9 +210,9 @@ static char *locate_in_PATH(const char *file)
 	return NULL;
 }
 
-static int exists_in_PATH(const char *file)
+int exists_in_PATH(const char *command)
 {
-	char *r = locate_in_PATH(file);
+	char *r = locate_in_PATH(command);
 	int found = r != NULL;
 	free(r);
 	return found;

run-command.h

@@ -182,6 +182,18 @@ void child_process_clear(struct child_process *);
 
 int is_executable(const char *name);
 
+/**
+ * Check if the command exists on $PATH. This emulates the path search that
+ * execvp would perform, without actually executing the command so it
+ * can be used before fork() to prepare to run a command using
+ * execve() or after execvp() to diagnose why it failed.
+ *
+ * The caller should ensure that command contains no directory separators.
+ *
+ * Returns 1 if it is found in $PATH or 0 if the command could not be found.
+ */
+int exists_in_PATH(const char *command);
+
 /**
  * Start a sub-process. Takes a pointer to a `struct child_process`
  * that specifies the details and returns pipe FDs (if requested).