diff --git a/.circleci/config.yml b/.circleci/config.yml
index 3129c3bd..c3674a9e 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -36,7 +36,7 @@ jobs:
             - v1-SRB2-APT
       - run:
           name: Install SDK
-          command: apt-get -qq -y --no-install-recommends install git build-essential nasm libpng12-dev:i386 libsdl2-mixer-dev:i386 libgme-dev:i386 gettext ccache wget gcc-multilib upx
+          command: apt-get -qq -y --no-install-recommends install git build-essential nasm libpng12-dev:i386 libsdl2-mixer-dev:i386 libgme-dev:i386 gettext ccache wget gcc-multilib upx openssh-client
       - save_cache:
           key: v1-SRB2-APT
           paths:
diff --git a/src/Makefile.cfg b/src/Makefile.cfg
index b6faf446..236d7ae2 100644
--- a/src/Makefile.cfg
+++ b/src/Makefile.cfg
@@ -116,6 +116,7 @@ WFLAGS+=-Wfloat-equal
 #WFLAGS+=-Wtraditional
 ifdef VCHELP
  WFLAGS+=-Wdeclaration-after-statement
+ WFLAGS+=-Wno-error=declaration-after-statement
 endif
  WFLAGS+=-Wundef
 ifndef GCC295
diff --git a/src/hardware/r_opengl/r_opengl.c b/src/hardware/r_opengl/r_opengl.c
index 3a8be6a0..0c4dfdce 100644
--- a/src/hardware/r_opengl/r_opengl.c
+++ b/src/hardware/r_opengl/r_opengl.c
@@ -2056,7 +2056,7 @@ EXPORT void HWRAPI(DrawMD2) (INT32 *gl_cmd_buffer, md2_frame_t *frame, FTransfor
 EXPORT void HWRAPI(SetTransform) (FTransform *stransform)
 {
 	static boolean special_splitscreen;
-	float used_fov;
+	double used_fov;
 	pglLoadIdentity();
 	if (stransform)
 	{
@@ -2088,7 +2088,7 @@ EXPORT void HWRAPI(SetTransform) (FTransform *stransform)
 	pglLoadIdentity();
 	if (special_splitscreen)
 	{
-		used_fov = atan(tan(used_fov*M_PI/360)*0.8)*360/M_PI;
+		used_fov = atan(tan(used_fov*M_PIl/360)*0.8)*360/M_PIl;
 		GLPerspective(used_fov, 2*ASPECT_RATIO);
 	}
 	else
diff --git a/src/k_kart.c b/src/k_kart.c
index cb8b71a0..544e3a30 100644
--- a/src/k_kart.c
+++ b/src/k_kart.c
@@ -1191,10 +1191,11 @@ void K_KartBouncing(mobj_t *mobj1, mobj_t *mobj2, boolean bounce, boolean solid)
 		return;
 
 	{ // Normalize distance to the sum of the two objects' radii, since in a perfect world that would be the distance at the point of collision...
-		fixed_t dist = P_AproxDistance(distx, disty) ?: 1;
+		fixed_t dist = P_AproxDistance(distx, disty);
 		fixed_t nx = FixedDiv(distx, dist);
 		fixed_t ny = FixedDiv(disty, dist);
 
+		dist = dist ? dist : 1;
 		distx = FixedMul(mobj1->radius+mobj2->radius, nx);
 		disty = FixedMul(mobj1->radius+mobj2->radius, ny);
 
diff --git a/src/p_user.c b/src/p_user.c
index 2f0998d7..f062a461 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -6662,7 +6662,7 @@ static void P_MovePlayer(player_t *player)
 				//CONS_Printf("leftover turn (%s): %5d or %4d%%\n",
 				//				player_names[player-players],
 				//				(INT16) (cmd->angleturn - (player->mo->angle>>16)),
-				//				(INT16) (cmd->angleturn - (player->mo->angle>>16)) * 100 / (angle_diff ?: 1));
+				//				(INT16) (cmd->angleturn - (player->mo->angle>>16)) * 100 / (angle_diff ? angle_diff : 1));
 			}
 		}
 
diff --git a/src/r_things.c b/src/r_things.c
index f8d84b03..25b02f58 100644
--- a/src/r_things.c
+++ b/src/r_things.c
@@ -1314,7 +1314,8 @@ static void R_ProjectSprite(mobj_t *thing)
 		if (max(tz, tz2) < FixedMul(MINZ, this_scale)) // non-papersprite clipping is handled earlier
 			return;
 
-		scalestep = (yscale2 - yscale)/(x2 - x1) ?: 1;
+		scalestep = (yscale2 - yscale)/(x2 - x1);
+		scalestep = scalestep ? scalestep : 1;
 
 		// The following two are alternate sorting methods which might be more applicable in some circumstances. TODO - maybe enable via MF2?
 		// sortscale = max(yscale, yscale2);