ci: cover all libbpf Makefile tutorials (#213)

* ci: cover all libbpf Makefile tutorials

* ci: build modules against HWE headers

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Co-authored-by: LinuxDev9002 <i@littlefisher.me>

src/features/dynptr/.config

@@ -8,4 +8,4 @@ btf=required
 kernel_config=CONFIG_BPF=y,CONFIG_BPF_SYSCALL=y,CONFIG_DEBUG_INFO_BTF=y,CONFIG_NET_CLS_BPF=y|m,CONFIG_NET_SCHED=y
 hardware=network-interface
 root=required
-test_status=not-in-ci
+test_status=ci-build

src/features/struct_ops/.config

@@ -7,4 +7,4 @@ btf=required
 kernel_config=CONFIG_BPF=y,CONFIG_BPF_SYSCALL=y,CONFIG_BPF_JIT=y,CONFIG_DEBUG_INFO_BTF=y,CONFIG_DEBUG_INFO_BTF_MODULES=y,CONFIG_MODULES=y
 hardware=none
 root=required
-test_status=not-in-ci
+test_status=ci-build

src/features/struct_ops/module/Makefile

@@ -2,10 +2,11 @@ obj-m += hello.o  # hello.o is the target
 
 # Enable BTF generation
 KBUILD_CFLAGS += -g -O2
+KDIR ?= /lib/modules/$(shell uname -r)/build
 
 all:
 	# Compile the module
-	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
+	+$(MAKE) -C $(KDIR) M=$(CURDIR) modules
 
 clean:
-	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
+	+$(MAKE) -C $(KDIR) M=$(CURDIR) clean