make: honor $CC (CC ?= cc) so a gcc environment builds with plain `make`

Change the hard `CC = cc` to `CC ?= cc` so an exported CC (e.g. CC=gcc) is
respected. Keeps the suckless default of cc for clones while letting a system
whose `cc` is shadowed use plain `make` without passing CC= each time.

Claude-Session: https://claude.ai/code/session_01S1CD1u3tgSS4xNu6WHfp5a

1 files changed, 1 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index fb6d964..aa3896e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 # clectio -- tiny, fast, suckless daily readings
 # Configure by editing config.h (copied from config.def.h on first build).
 
-CC      = cc
+CC     ?= cc
 CFLAGS  = -std=c99 -Os -Wall -Wextra
 LDFLAGS = -s
 PREFIX  = /usr/local