diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b3858ac3..a6f32ee6 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -30,7 +30,7 @@ jobs:
           { "name": "gcc-no-math",
             "flags":
               '{ "QMAKESPEC": "linux-gcc-no-math",
-                 "EVAL": "export CXX=false && touch src/math.h src/float.h",
+                 "EVAL": "export CXX=false && touch math.h float.h",
                  "CFLAGS": "-ffreestanding -DCBOR_NO_FLOATING_POINT -Os",
                  "LDFLAGS": "-Wl,--no-undefined",
                  "LDLIBS": ""
diff --git a/Makefile.configure b/Makefile.configure
index 16bab6bb..d906ef1b 100644
--- a/Makefile.configure
+++ b/Makefile.configure
@@ -15,11 +15,12 @@ PROGRAM-freestanding += int main() {}
 CCFLAGS-freestanding = $(CFLAGS)
 
 PROGRAM-cjson  = \#include <stdlib.h>\n
+PROGRAM-cjson += \#include <math.h>\n
 PROGRAM-cjson += \#include <cjson/cJSON.h>\n
-PROGRAM-cjson += int main() { return cJSON_False; }
-CCFLAGS-cjson = -I$(dir $(MAKEFILE))src
+PROGRAM-cjson += int main() { double d = NAN; return cJSON_False; }
+CCFLAGS-cjson = -I. -I$(dir $(MAKEFILE))src
 PROGRAM-system-cjson = $(PROGRAM-cjson)
-CCFLAGS-system-cjson = -lcjson
+CCFLAGS-system-cjson = -I. -lcjson
 
 sink:
 	@echo >&2 Please run from the top-level Makefile.