diff -Naur ORIG/configure.ac PATCHED/configure.ac
--- ORIG/configure.ac	2026-04-07 20:20:41.990906351 +0000
+++ PATCHED/configure.ac	2026-04-07 20:20:41.991000971 +0000
@@ -47,6 +47,7 @@
 AC_PROG_INSTALL
 AC_PROG_LN_S
 
+if test "x$MYFFLAGS" = "x"; then
 if test "x$F77" = "xg77"; then
   AC_SUBST([MYFFLAGS], ["-fno-automatic -finit-local-zero -fno-backslash -fno-globals -ff90 -fpic -ffixed-line-length-132"])
   AC_MSG_RESULT([Using g77 with FLAGS = $MYFFLAGS ])
@@ -56,6 +57,9 @@
   AC_SUBST([MYFFLAGS], ["-O0 -fno-automatic -fno-backslash -fbounds-check -fpic -ffixed-line-length-132 -Wl,-flat_namespace "]) 
   AC_MSG_RESULT([Using gfortran with FLAGS = $MYFFLAGS ])
 fi
+else
+AC_SUBST([MYFFLAGS], [$MYFFLAGS]) 
+fi
 
 
 
diff -Naur ORIG/src/Makefile.am PATCHED/src/Makefile.am
--- ORIG/src/Makefile.am	2026-04-07 20:20:41.990945946 +0000
+++ PATCHED/src/Makefile.am	2026-04-07 20:20:41.991155035 +0000
@@ -109,5 +109,5 @@
 
 lib_LTLIBRARIES = libhztool.la
 AM_LDFLAGS = $(VERSIONFLAGS)
-AM_FFLAGS = -I$(top_srcdir)/inc $(MYFFLAGS)
+AM_FFLAGS = -I$(top_srcdir)/inc $(MYFFLAGS) $(FFLAGS)
 libhztool_la_SOURCES = $(TOOLSSOURCES) $(PAPERSSOURCES)
diff -Naur ORIG/src/hera/hzh0006017.F PATCHED/src/hera/hzh0006017.F
--- ORIG/src/hera/hzh0006017.F	2026-04-07 20:20:41.991000971 +0000
+++ PATCHED/src/hera/hzh0006017.F	2026-04-07 20:20:41.991170698 +0000
@@ -144,13 +144,14 @@
 *
       real cs1(ptbn,ybn),cs1ste(ptbn,ybn)
       real cs1sye(ptbn,ybn),cs1te(ptbn,ybn),yav(ybn),ptav(ptbn)
-      real arh1(ybn+1),arh1e(ybn+1),arh1s(ybn+1)
+      real arh1(ybn+1)
       real arh2(ptbn),arh2e(ptbn),arh2s(ptbn)
 * 
 * for cs as function of xf (fig6)
 *
       real xfav(xbn),cs2(xbn),cs2ste(xbn),cs2sye(xbn),cs2te(xbn)
-      real zero2(ptbn), zero3(xbn)
+      double precision  zero3(xbn),arh1e(ybn+1),arh1s(ybn+1)
+      double precision  zero2(ptbn)
 *
 * data for figures 2 and 3 [d^2s/dpt^2dy]
 *
