diff --git a/.github/workflows/test/build-php-ext-gsl.sh b/.github/workflows/test/build-php-ext-gsl.sh
index de2995c..2e22150 100755
--- a/.github/workflows/test/build-php-ext-gsl.sh
+++ b/.github/workflows/test/build-php-ext-gsl.sh
@@ -8,7 +8,7 @@ php --version
 cd php-ext-gsl
 
 phpize
-./configure
+./configure --with-gsl CFLAGS="$CFLAGS -Wno-implicit-function-declaration"
 php -dmemory_limit=-1 build/gen_stub.php --force-regeneration
 sed -i 's/$user_input = fgets($fp, 10);/$user_input = "s";/g' run-tests.php
 make
\ No newline at end of file