From which Makefile does the error come from

Question

I'am trying to undrestand the build process of openwrt. basically i'am adding traces using $(warning), commenting some instructions and so on.

At some point i run make world and face an error. My problem is that i forget in which files exactly i made changes.

This is make error output after the command make -d world :

Reading makefile `tp-link.mk' (search path) (no ~ expansion)...
Reading makefile `ubnt.mk' (search path) (no ~ expansion)...
Reading makefile `generic.mk' (search path) (no ~ expansion)...
Reading makefile `legacy.mk' (search path) (no ~ expansion)...
Makefile:102: *** commands commence before first target.  Stop.
Reaping losing child 0x008a0f20 PID 3213 
make[5]: *** [image-prereq] Error 2
Removing child 0x008a0f20 PID 3213 from chain.
Reaping losing child 0x0257c930 PID 3210 
make[4]: *** [prereq] Error 2
Removing child 0x0257c930 PID 3210 from chain.
Reaping losing child 0x01196730 PID 3207 
make[3]: *** [target/linux/prereq] Error 2
Removing child 0x01196730 PID 3207 from chain.
Reaping losing child 0x01432210 PID 3194 
make[2]: *** [/home/user/Bureau/Workspace/arduino/openwrt-yun_2/openwrt/staging_dir/target-mips_34kc_musl-1.1.15/stamp/.target_prereq] Error 2
Removing child 0x01432210 PID 3194 from chain.
Reaping losing child 0x01cb58c0 PID 3189 
make[1]: *** [prereq] Error 2
Removing child 0x01cb58c0 PID 3189 from chain.
Récupération du statut de sortie du processus fils 0x0167e4a0 PID 3074 
make: *** [world] Erreur 2
Suppression du processus fils 0x0167e4a0 PID 3074 de la chaîne.

what i undrestand from this output is that make is complaining about an error on line 102 when trying to read legacy.mk. I'am sure that i didn't make any change on this file.

My question:

How can we use make debug option to know from which Makefile the problem come ?

Answer 1

Problem resolved: by mistake i have replaced a 2 space by a tab in the file image.mk line 605. The make error message was really not helpful.

How i find the mistake: The most obvious solution git checkout ,then meld the modified files.