Hi Mekeor, Remove the quote after arguments (replace it with a plain LIST call) and add #~ before (modify-phases ...) to define a gexp.
Untested example: (arguments (list #:tests? #f ; no tests #:make-flags (list "CC=gcc") #:phases #~(modify-phases %standard-phases (delete 'configure) (add-after 'unpack 'patch-makefile (lambda _ (substitute* "Makefile" (("/usr/local") #$output))))))) Also, newlines after ( make the baby Jesus cry. So does hard-coding 'gcc' over using (cc-for-target). Very strong opinions on Scheme coding style, that boy. Kind regards, T G-R Sent on the go. Excuse or enjoy my brevity.