diff --git a/.travis.yml b/.travis.yml
index 30a3f5b6..e89ef22e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,20 +3,6 @@ services:
   - docker
 matrix:
   include:
-  - os: linux
-    addons:
-      apt:
-        sources:
-          - ubuntu-toolchain-r-test
-        packages:
-          - gcc-5
-          - g++-5
-    env: >-
-      TRAVIS_OS_NAME=linux
-      TRAVIS_BUILD_SYSTEM=Makefile
-      HYPERROGUE_CXX=g++-5
-      HYPERROGUE_USE_GLEW=1
-      HYPERROGUE_USE_PNG=1
   - os: linux
     compiler: gcc
     env: >-
@@ -34,6 +20,23 @@ matrix:
       HYPERROGUE_USE_GLEW=1
       HYPERROGUE_USE_PNG=1
   - os: linux
+    compiler: gcc
+    env: >-
+      TRAVIS_OS_NAME=linux
+      TRAVIS_COMPILER_NAME=gcc
+      TRAVIS_BUILD_SYSTEM=Makefile
+      HYPERROGUE_USE_GLEW=1
+      HYPERROGUE_USE_PNG=1
+  - os: linux
+    compiler: clang
+    env: >-
+      TRAVIS_OS_NAME=linux
+      TRAVIS_COMPILER_NAME=clang
+      TRAVIS_BUILD_SYSTEM=Makefile
+      HYPERROGUE_USE_GLEW=1
+      HYPERROGUE_USE_PNG=1
+  - os: linux
+    dist: bionic
     compiler: gcc
     env: >-
       TRAVIS_OS_NAME=linux
@@ -51,6 +54,14 @@ matrix:
       HYPERROGUE_USE_GLEW=1
       HYPERROGUE_USE_PNG=1
       HYPERROGUE_USE_ROGUEVIZ=1
+  - os: osx
+    compiler: clang
+    env: >-
+      TRAVIS_OS_NAME=osx
+      TRAVIS_COMPILER_NAME=clang
+      TRAVIS_BUILD_SYSTEM=Makefile
+      HYPERROGUE_USE_GLEW=1
+      HYPERROGUE_USE_PNG=1
   - os: osx
     compiler: gcc
     env: >-
@@ -69,15 +80,6 @@ matrix:
       HYPERROGUE_USE_GLEW=1
       HYPERROGUE_USE_PNG=1
       HYPERROGUE_USE_ROGUEVIZ=1
-  - os: osx
-    compiler: clang
-    env: >-
-      TRAVIS_OS_NAME=osx
-      TRAVIS_COMPILER_NAME=clang
-      TRAVIS_BUILD_SYSTEM=Makefile
-      HYPERROGUE_USE_GLEW=0
-      HYPERROGUE_USE_PNG=0
-      HYPERROGUE_USE_ROGUEVIZ=0
   - os: linux
     env: >-
       TRAVIS_OS_NAME=linux
@@ -140,7 +142,7 @@ script:
     ./configure CXXFLAGS="-W -Wall -Wextra -Werror -Wno-unused-parameter -Wno-maybe-uninitialized -Wno-unknown-warning-option"
     make
   elif [[ "$TRAVIS_BUILD_SYSTEM" == "Makefile" ]]; then
-    make -f Makefile.simple CXX="${HYPERROGUE_CXX-g++}"
+    make -f Makefile.simple
   elif [[ "$TRAVIS_BUILD_SYSTEM" == "emscripten" ]]; then
     docker run --rm -v $(pwd):/src trzeci/emscripten make -f Makefile.simple emscripten
   else
diff --git a/Makefile.simple b/Makefile.simple
index b9e55f66..014ccf1e 100644
--- a/Makefile.simple
+++ b/Makefile.simple
@@ -80,19 +80,22 @@ ifeq (${OS},osx)
 endif
 
 ifeq (${TOOLCHAIN},clang)
-  CXXFLAGS_EARLY += -std=c++11 -march=native
+  CXXFLAGS_STD = -std=c++11
+  CXXFLAGS_EARLY += -march=native
   CXXFLAGS_EARLY += -W -Wall -Wextra -Werror -pedantic
   CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-implicit-fallthrough -Wno-maybe-uninitialized -Wno-unknown-warning-option
 endif
 
 ifeq (${TOOLCHAIN},gcc)
-  CXXFLAGS_EARLY += -std=c++11 -march=native
+  CXXFLAGS_STD = -std=c++11
+  CXXFLAGS_EARLY += -march=native
   CXXFLAGS_EARLY += -W -Wall -Wextra -Werror -pedantic
   CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-implicit-fallthrough -Wno-maybe-uninitialized
 endif
 
 ifeq (${TOOLCHAIN},mingw)
-  CXXFLAGS_EARLY += -std=c++11 -march=native
+  CXXFLAGS_STD = -std=c++11
+  CXXFLAGS_EARLY += -march=native
   CXXFLAGS_EARLY += -W -Wall -Wextra -Werror
   CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-implicit-fallthrough -Wno-maybe-uninitialized
 endif
@@ -121,7 +124,8 @@ else
 endif
 
 ifeq (${HYPERROGUE_USE_ROGUEVIZ},1)
-  # Enable RogueViz.
+  # Enable RogueViz. RogueViz requires C++17.
+  CXXFLAGS_STD = -std=c++17
   CXXFLAGS_EARLY += -DCAP_ROGUEVIZ=1
 endif
 
@@ -130,7 +134,7 @@ endif
 ## Begin the Makefile proper.
 
 
-override CXXFLAGS := $(CXXFLAGS_EARLY) $(CXXFLAGS) ${EXTRA_CXXFLAGS}
+override CXXFLAGS := $(CXXFLAGS_STD) $(CXXFLAGS_EARLY) $(CXXFLAGS) ${EXTRA_CXXFLAGS}
 override LDFLAGS := $(LDFLAGS_EARLY) $(LDFLAGS) ${EXTRA_LDFLAGS}
 
 hyperrogue$(EXE_EXTENSION): $(hyper_OBJS) $(hyper_RES)