Summary:
Hardcoding `variable@` in Makefiles is Bad™ because it prevents the users from
overwriting them easily with `make variable="my custom value"`. The right way
to do it is thus:
```
variable = variable@
# then use $(variable) everywhere
```
This diff puts all the `variable = variable@` lines in Makefile.config.in, and
changes every occurrence of a `variable@` to `$(variable)` everywhere else.
I mostly automated generating this diff. Here are the steps I did:
- find out which `variable@`s we use:
find . -name 'Makefile*' -exec grep -e '@[^@ []\+@' -o -h \{\} \+ | sort | uniq > config_variables
- write this `replace.sh` script to replace every `variable@` with `$(variable)`:
```
#!/bin/sh
config_vars_file=$1
shift
for line in $(cat $config_vars_file); do
var=$(echo $line | tr -d @)
sed -i -e "s/$line/\$($var)/g" $@ > /dev/null
done
```
- run the script as such:
find . -name 'Makefile.*in' \( -not -wholename './Makefile.config.in' \) -exec ./replace.sh config_variables \{\} \+
- put all the `VARIABLE = VARIABLE@` lines in Makefile.config.in
- move all `Makefile.in` to `Makefile`, since they don't need to be generated by `./configure` anymore:
```
for i in $(find . -name 'Makefile.*in' \( -not -wholename './Makefile.config.in' \)); do \
rm $(dirname $i)/$(basename $i .in) && git mv $i $(dirname $i)/$(basename $i .in) ; \
done
```
- delete all Makefile except Makefile.config from configure.ac
- manually inspect and remove remaining instances of `VAR = $(VAR)` in makefiles, looking at the output of `git grep '^\(\w\+\) = $(\1)'`
Reviewed By: jberdine
Differential Revision: D3358379
fbshipit-source-id: 5d37f02
Jules Villard