Check for remote url instead of .git existence

Current implementation of .git checking have some issues:
- If a kernel source being cloned using git-repo tool, especially
newer version, it will clone .git in .repo inside of the submodule
source.
- Newer kernel source changed how $(src) & $(srctree) output. In
the case of kernel 6.11 as I tested $(src) show the relative path
of the symlink in drivers/ instead of KernelSU main directory.
Which makes checking for ../.git existence comletely useless.

One idea I would like to propose is to check for the remote URL in
$(src). If the remote is correct then we can assume this is
KSU repo and then count the version (also unshallow the repo).
Here's what I did:
- Check if kernel is 6.9+ and then change $(src) accordingly.
- Print $(src) remote in verbose and check for the correct
 URL (both ssh & https).
- If correct, check if the repo is shallow by using
git rev-parse --is-shallow-repository. Unshallow if it's return true.
- Calculate version as usual.

The only drawback I can see so far is that forks will have to edit
the url in the Makefile, which I don't think it's much of an issue.

Signed-off-by: hmtheboy154 <[email protected]>

Author: hmtheboy154

kernel/Makefile

@@ -16,15 +16,36 @@ ccflags-y += -I$(objtree)/security/selinux -include $(srctree)/include/uapi/asm-
 
 obj-$(CONFIG_KSU) += kernelsu.o
 
-# .git is a text file while the module is imported by 'git submodule add'.
-ifeq ($(shell test -e $(srctree)/$(src)/../.git; echo $$?),0)
-$(shell cd $(srctree)/$(src); /usr/bin/env PATH="$$PATH":/usr/bin:/usr/local/bin [ -f ../.git/shallow ] && git fetch --unshallow)
-KSU_GIT_VERSION := $(shell cd $(srctree)/$(src); /usr/bin/env PATH="$$PATH":/usr/bin:/usr/local/bin git rev-list --count HEAD)
+IS_KERNEL_69 := $(strip $(shell \
+    if [ "$(VERSION)" -ge "6" -a "$(PATCHLEVEL)" -ge "9" ]; then \
+      echo TRUE; \
+    else \
+      echo FALSE; \
+    fi \
+  ))
+
+# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b1992c3772e69a6fd0e3fc81cd4d2820c8b6eca0
+ifeq ($(IS_KERNEL_69),TRUE)
+SRC_LOCATION := $(src)
+else
+SRC_LOCATION := $(srctree)/$(src)
+endif
+
+GIT_TOOL := /usr/bin/env PATH="$$PATH":/usr/bin:/usr/local/bin git
+
+# Check for both https & ssh remote
+REMOTE_CHECK := $(shell cd $(SRC_LOCATION); $(GIT_TOOL) remote -v | grep -E 'github\.com[/:]tiann/KernelSU')
+
+ifneq ($(REMOTE_CHECK),)
+ifeq ($(shell cd $(SRC_LOCATION); $(GIT_TOOL) rev-parse --is-shallow-repository),true)
+$(shell cd $(SRC_LOCATION); $(GIT_TOOL) fetch --unshallow)
+endif
+KSU_GIT_VERSION := $(shell cd $(SRC_LOCATION); $(GIT_TOOL) rev-list --count HEAD)
 # ksu_version: major * 10000 + git version + 200 for historical reasons
 $(eval KSU_VERSION=$(shell expr 10000 + $(KSU_GIT_VERSION) + 200))
 $(info -- KernelSU version: $(KSU_VERSION))
 ccflags-y += -DKSU_VERSION=$(KSU_VERSION)
-else # If there is no .git file, the default version will be passed.
+else # Pass default version if the defined remote is not found
 $(warning "KSU_GIT_VERSION not defined! It is better to make KernelSU a git submodule!")
 ccflags-y += -DKSU_VERSION=16
 endif