fatal error: 'google/protobuf/compiler/plugin.h' file not found - import

Question

I'm compiling a Google protobuf plugin from these sources.
I've installed protobuf#2.5 with the homebrew command:
brew install protobuf#2.5
After installation I get the following error when trying to compile by calling make:
Richards-Mac-mini:protobuf-objc-arc richard$ make
/Applications/Xcode.app/Contents/Developer/usr/bin/make all-recursive
Making all in src/compiler
g++ -DHAVE_CONFIG_H -I. -I../.. -g -O2 -DNDEBUG -MT main.o -MD -MP -MF .deps/main.Tpo -c -o main.o main.cc
main.cc:17:10: fatal error: 'google/protobuf/compiler/plugin.h' file not found
#include <google/protobuf/compiler/plugin.h>
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [main.o] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
In particular, this line is interesting:
fatal error: 'google/protobuf/compiler/plugin.h' file not found
While I definitely able to go to this path and find the plugin.h file:
/usr/local/Cellar/protobuf#2.5/2.5.0/include/google/protobuf/compiler/plugin.h
Looks, like the library is not linked correctly with the binary and the issue is somehow related to the correct path.
When I try to issue a command which protoc, I get:
/usr/local/opt/protobuf#2.5/bin/protoc
protoc --version leads to the following output, which is expected.
libprotoc 2.5.0

Answer 1

Fixed by issuing the following commands:
brew link --force --overwrite protobuf250
Output:
Linking /usr/local/Cellar/protobuf#2.5/2.5.0... 14 symlinks created
If you need to have this software first in your PATH instead consider running:
echo 'export PATH="/usr/local/opt/protobuf#2.5/bin:$PATH"' >> ~/.bash_profile
And then:
echo 'export PATH="/usr/local/opt/protobuf#2.5/bin:$PATH"' >>
~/.bash_profile
After successful linking I was able to compile the Objective-C plugin without errors.