diff --git a/src/configure b/src/configure
index 2f0f9be01c..662f82231c 100755
--- a/src/configure
+++ b/src/configure
@@ -5321,19 +5321,16 @@ case $OS in
       fi
     fi
 
-    # Force 32-bit build, for now
+    # Force 32-bit build unless mac64 is enabled:
     if test "${enable_mac64}" != "yes" ; then
       if test `${UNAME} -m` = "i386" ; then
         if test "${ORIG_CC}" = "" ; then
-           CC="${CC} -m32"
-           SUB_CONFIGURE_EXTRAS="${SUB_CONFIGURE_EXTRAS} CC="'"'"${CC}"'"'
-        fi
-        if test "${ORIG_CPP}" = "" ; then
-           CPP="${CPP} -m32"
-           SUB_CONFIGURE_EXTRAS="${SUB_CONFIGURE_EXTRAS} CPP="'"'"${CPP}"'"'
-        fi
-        if test "${ORIG_CC_FOR_BUILD}" = "" ; then
-           CC_FOR_BUILD="${CC_FOR_BUILD} -m32"
+           PREFLAGS="${PREFLAGS} -m32"
+           CPPFLAGS="${CPPFLAGS} -m32"
+           LDFLAGS="${LDFLAGS} -m32"
+           # To make the libffi build work, we have to fold -m32 into CC
+           # instead of CFLAGS:
+           SUB_CONFIGURE_EXTRAS="${SUB_CONFIGURE_EXTRAS} CC="'"'"${CC}"' -m32"'
         fi
       fi
     fi
diff --git a/src/gracket/gc2/Makefile.in b/src/gracket/gc2/Makefile.in
index a754d50d4a..633242697f 100644
--- a/src/gracket/gc2/Makefile.in
+++ b/src/gracket/gc2/Makefile.in
@@ -69,7 +69,7 @@ wx_mac_EXTRAFLAGS =
 EXTRAFLAGS = $(@WXVARIANT@_EXTRAFLAGS)
 
 grmain.@LTO@: xsrc/grmain.c
-	$(CC) $(EXTRAFLAGS) -DGC2_JUST_MACROS $(GCPREINC) -c $(POSTFLAGS) -o grmain.@LTO@ xsrc/grmain.c
+	$(CC) $(CFLAGS) $(EXTRAFLAGS) -DGC2_JUST_MACROS $(GCPREINC) -c $(POSTFLAGS) -o grmain.@LTO@ xsrc/grmain.c
 
 XSRCS = xsrc/grmain.c
 
diff --git a/src/plot/Makefile.in b/src/plot/Makefile.in
index e0350a7adb..b3f110b85a 100644
--- a/src/plot/Makefile.in
+++ b/src/plot/Makefile.in
@@ -12,12 +12,7 @@ ICP=@ICP@
 
 CC = @CC@
 
-# Setting the compiler and linker when using dynext
-#   seems like a good idea, but it doesn't work with
-#  libtool as the compiler. So, we trust the configuration
-#  that is built into dynext, instead.
-# WITH-ENV = env CC="$(CC)" LD="@MZLINKER@" ...
-WITH_ENV = env CFLAGS="@CFLAGS@ @COMPFLAGS@ @PREFLAGS@" LDFLAGS="@LDFLAGS@"
+WITH_ENV = env CC="@PLAIN_CC@" CFLAGS="@CFLAGS@ @COMPFLAGS@ @PREFLAGS@" LDFLAGS="@LDFLAGS@"
 
 PLPLOT_SRCS = $(srcdir)/plplot/dc_drv.c \
               $(srcdir)/plplot/plcont.c \
diff --git a/src/racket/configure.ac b/src/racket/configure.ac
index 902d270c4b..55d85ec31e 100644
--- a/src/racket/configure.ac
+++ b/src/racket/configure.ac
@@ -16,7 +16,7 @@
 #  GC2OPTIONS - GC2-only flags
 #
 # Note: we use CPPFLAGS for configure-time testing only because
-# it needs to include C++ flags that we don't want for Racket.
+# it used to include C++ flags that we didn't want for Racket.
 # hence PREFLAGS, which is initialized to the original CPPFLAGS.
 
 AC_INIT([Racket])
@@ -651,19 +651,16 @@ case $OS in
       fi
     fi
 
-    # Force 32-bit build, for now
+    # Force 32-bit build unless mac64 is enabled:
     if test "${enable_mac64}" != "yes" ; then
       if test `${UNAME} -m` = "i386" ; then
         if test "${ORIG_CC}" = "" ; then
-           CC="${CC} -m32"
-           SUB_CONFIGURE_EXTRAS="${SUB_CONFIGURE_EXTRAS} CC="'"'"${CC}"'"'
-        fi
-        if test "${ORIG_CPP}" = "" ; then
-           CPP="${CPP} -m32"
-           SUB_CONFIGURE_EXTRAS="${SUB_CONFIGURE_EXTRAS} CPP="'"'"${CPP}"'"'
-        fi
-        if test "${ORIG_CC_FOR_BUILD}" = "" ; then
-           CC_FOR_BUILD="${CC_FOR_BUILD} -m32"
+           PREFLAGS="${PREFLAGS} -m32"
+           CPPFLAGS="${CPPFLAGS} -m32"
+           LDFLAGS="${LDFLAGS} -m32"
+           # To make the libffi build work, we have to fold -m32 into CC
+           # instead of CFLAGS:
+           SUB_CONFIGURE_EXTRAS="${SUB_CONFIGURE_EXTRAS} CC="'"'"${CC}"' -m32"'
         fi
       fi
     fi
diff --git a/src/racket/gc/Makefile.in b/src/racket/gc/Makefile.in
index 5c442c0470..c246bd0fca 100644
--- a/src/racket/gc/Makefile.in
+++ b/src/racket/gc/Makefile.in
@@ -434,7 +434,7 @@ CURSES= -lcurses -ltermlib
 # the SHELL environment variable.
 SHELL= /bin/sh
 
-SPECIALCFLAGS = -I$(srcdir)/include -I$(AO_INSTALL_DIR)/include
+SPECIALCFLAGS = -I$(srcdir)/include -I$(AO_INSTALL_DIR)/include @CFLAGS@ @COMPFLAGS@ @PREFLAGS@
 # Alternative flags to the C compiler for mach_dep.c.
 # Mach_dep.c often doesn't like optimization, and it's
 # not time-critical anyway.