semaphore: bump gcc from gcc5 to gcc7

Author: mrc0mmand

test/semaphore-run

@@ -19,7 +19,7 @@ set -eu
 (
     set -x
 
-    sudo apt install -y software-properties-common
+    sudo apt install -y gcc-7 libgcc-7-dev software-properties-common
     sudo apt -y update
     sudo apt -y --no-install-recommends install \
          python3.6 \
@@ -71,7 +71,7 @@ echo "============= Installing i386 build dependencies =============="
     sudo apt remove -y libcurl4-openssl-dev
     sudo apt-get install -y --no-install-recommends \
          gcc-multilib \
-         libgcc-5-dev:i386 \
+         libgcc-7-dev:i386 \
          "${DEVPKGS[@]/%/:i386}"
 )
 
@@ -80,7 +80,7 @@ echo "============= Building i386 =============="
 (
     set -x
     export PKG_CONFIG_PATH=/usr/lib/i386-linux-gnu
-    CC=gcc-5 CFLAGS=-m32 LDFLAGS=-m32 meson build-i386
+    CC=gcc-7 CFLAGS=-m32 LDFLAGS=-m32 meson build-i386
     ninja -C build-i386
 )