Create an extras directory with files that are not related to the build but that I need to keep around for reference.

PPP3/extras/process.diff

@@ -0,0 +1,23 @@
+--- subprojects/libgit2-1.8.0/src/util/process.h	2024-03-20 16:19:37.000000000 -0400
++++ process.h	2024-05-09 08:05:48.279986200 -0400
+@@ -8,6 +8,8 @@
+ #ifndef INCLUDE_process_h__
+ #define INCLUDE_process_h__
+ 
++typedef struct git_str git_str;
++
+ typedef struct git_process git_process;
+ 
+ typedef struct {
+@@ -112,10 +114,7 @@
+  * cmdline arguments to ensure that they are not erroneously treated
+  * as an option. For example, arguments to `ssh`.
+  */
+-GIT_INLINE(bool) git_process__is_cmdline_option(const char *str)
+-{
+-	return (str && str[0] == '-');
+-}
++#define git_process__is_cmdline_option(str) ((str) && (str[0]) == '-')
+ 
+ /**
+  * Start the process.