diff --git a/src/frontend/numparam/mystring.c b/src/frontend/numparam/mystring.c
index 96e9d1a63..d5f2c5ad0 100644
--- a/src/frontend/numparam/mystring.c
+++ b/src/frontend/numparam/mystring.c
@@ -8,11 +8,11 @@
 #include <stdlib.h>
 #include <ctype.h>
 #include <string.h>
-#include "ngspice/memory.h"
 #include <math.h>
 #include <stdarg.h>
 
 #include "ngspice/config.h"
+#include "ngspice/memory.h"
 #ifdef HAS_WINGUI
 #include "ngspice/wstdio.h"
 #endif
diff --git a/src/maths/fft/fftext.c b/src/maths/fft/fftext.c
index d13c94247..c927965a5 100644
--- a/src/maths/fft/fftext.c
+++ b/src/maths/fft/fftext.c
@@ -15,6 +15,7 @@
 #include "fftlib.h"
 #include "matlib.h"
 #include "ngspice/fftext.h"
+#include "ngspice/config.h"
 #include "ngspice/memory.h"
 
 #ifndef M_PI
diff --git a/src/maths/sparse/spdefs.h b/src/maths/sparse/spdefs.h
index 5a76a191c..fd5237ca7 100644
--- a/src/maths/sparse/spdefs.h
+++ b/src/maths/sparse/spdefs.h
@@ -372,6 +372,7 @@ extern void * trealloc(void *, size_t);
 #define SP_FREE(ptr) { if ((ptr) != NULL) txfree(ptr); (ptr) = NULL; }
 
 
+#include "ngspice/config.h"
 
 /* A new calloc */
 #ifndef HAVE_LIBGC
@@ -382,6 +383,11 @@ extern void * trealloc(void *, size_t);
 #define SP_CALLOC(ptr,type,number)                           \
 { ptr = (type *) tmalloc((size_t)(number) * sizeof(type));   \
 }
+#include <gc/gc.h>
+#define tmalloc(m)      GC_malloc(m)
+#define trealloc(m, n)  GC_realloc((m), (n))
+#define tfree(m)
+#define txfree(m)
 #endif
 
 #include "ngspice/defines.h"