Problem

I've upgraded to using libgit2 v1.9, and I've been getting build errors that weren't there previously. This is caused by the custom <stdint.h> header file.

The build errors only occur when using a installed libgit2.
I am using Fedora Linux 41.

Example usage code

CMakeLists.txt

cmake_minimum_required(VERSION 3.30)
project(using_libgit2)
add_executable(my_exe main.cpp)
find_package(libgit2)
target_link_libraries(my_exe PRIVATE libgit2::libgit2package)

main.cpp

#include <cstdint>
int main() {
    return 0;
}

Trying to build this leads to errors like this:

/usr/include/c++/14/cstdint:51:11: error: ‘int8_t’ has not been declared in ‘::’
   51 |   using ::int8_t;

Explanation

When using the installed libgit2 the include paths will now contain include/git2 instead of include. This is problematic because there's a custom <stdint.h> in the git2 folder.
Now any user code that has #include <stdint.h>, will now include the custom <stdint.h> header instead of the standard one. Which causes the build error.

Solution

This PR fixes this regression.