This appears to me when I try to install MM, using sudo gem…
ERROR: Error installing middleman:
ERROR: Failed to build gem native extension.
current directory: /var/lib/gems/2.5.0/gems/fast_blank-1.0.0/ext/fast_blank
/usr/bin/ruby2.5 -r ./siteconf20181213-22176-rehktj.rb extconf.rb
creating Makefile
current directory: /var/lib/gems/2.5.0/gems/fast_blank-1.0.0/ext/fast_blank
make "DESTDIR=" clean
current directory: /var/lib/gems/2.5.0/gems/fast_blank-1.0.0/ext/fast_blank
make "DESTDIR="
compiling fast_blank.c
make: gcc: Command not found
Makefile:242: recipe for target 'fast_blank.o' failed
make: *** [fast_blank.o] Error 127
make failed, exit code 2
Gem files will remain installed in /var/lib/gems/2.5.0/gems/fast_blank-1.0.0 for inspection.
Results logged to /var/lib/gems/2.5.0/extensions/x86_64-linux/2.5.0/fast_blank-1.0.0/gem_make.out
Please some good soul may help me out? I tried re installing Ruby, Gems and nothing, those are clearly installed in the last version.
If it is better to open an issue instead of coming here, just tell me, cheers!