add gcc to build

ci.Dockerfile

@@ -5,7 +5,8 @@ WORKDIR /app
 
 COPY go.mod .
 
-RUN pacman -Sy && pacman -S --overwrite=* --noconfirm archlinux-keyring && pacman -Su --overwrite=* --needed --noconfirm go git && \
+RUN pacman -Sy && pacman -S --overwrite=* --noconfirm archlinux-keyring && \
+    pacman -Su --overwrite=* --needed --noconfirm go git gcc && \
     rm -rfv /var/cache/pacman/* /var/lib/pacman/sync/* && \
     curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s v1.50.1 && \
     go mod download