diff --git a/repos/libports/lib/mk/solo5.mk b/repos/libports/lib/mk/solo5.mk
index 20da4ab8f2..92fadf36b2 100644
--- a/repos/libports/lib/mk/solo5.mk
+++ b/repos/libports/lib/mk/solo5.mk
@@ -4,6 +4,11 @@ SHARED_LIB = yes
 
 CC_OPT += -D__SOLO5_BINDINGS__ -Drestrict=__restrict__
 
+# GCC 8 complains about a mismatch of the 'log()' function declaration.
+# Since the solo5 'log()' function is unrelated to the builtin function,
+# we disable the error message.
+CC_OPT += -Wno-builtin-declaration-mismatch
+
 SRC_CC = bindings.cc
 
 SOLO5_PORT_DIR := $(call select_from_ports,solo5)