diff --git a/build-aux/bootstrap.sh.in b/build-aux/bootstrap.sh.in
index 192508a7..3665a0ec 100644
--- a/build-aux/bootstrap.sh.in
+++ b/build-aux/bootstrap.sh.in
@@ -30,22 +30,22 @@ MES_PREFIX=${MES_PREFIX-$PWD}
 . build-aux/configure-lib.sh
 
 CPPFLAGS="-D HAVE_CONFIG_H=1 -I include"
-CFLAGS=""
+AM_CFLAGS=""
 mkdir -p mescc-lib
 cp config.sh mescc-lib/config.sh
 cd mescc-lib
 srcdest=../
-CPPFLAGS="-D HAVE_CONFIG_H=1 -I ${srcdest}include -I ${srcdest}include/$mes_kernel/$mes_cpu"
+AM_CPPFLAGS="-D HAVE_CONFIG_H=1 -I ${srcdest}include -I ${srcdest}include/$mes_kernel/$mes_cpu"
 
 mkdir $mes_cpu-mes
-$CC -c $CPPFLAGS $CFLAGS ${srcdest}lib/$mes_kernel/$mes_cpu-mes-$compiler/crt1.c
+$CC -c $AM_CPPFLAGS $CPPFLAGS $AM_CFLAGS $CFLAGS ${srcdest}lib/$mes_kernel/$mes_cpu-mes-$compiler/crt1.c
 cp crt1.o $mes_cpu-mes
 cp crt1.s $mes_cpu-mes
 
 objects=
 for c in $libc_mini_SOURCES; do
     echo "CC         $c"
-    $CC -c $CPPFLAGS $CFLAGS ${srcdest}$c
+    $CC -c $AM_CPPFLAGS $CPPFLAGS $AM_CFLAGS $CFLAGS ${srcdest}$c
     o=$(basename $c .c).o
     objects="$objects $o"
 done
@@ -55,7 +55,7 @@ $AR crD $mes_cpu-mes/libc-mini.a $objects
 objects=
 for c in $libc_SOURCES; do
     echo "CC         $c"
-    $CC -c $CPPFLAGS $CFLAGS ${srcdest}$c
+    $CC -c $AM_CPPFLAGS $CPPFLAGS $AM_CFLAGS $CFLAGS ${srcdest}$c
     o=$(basename $c .c).o
     objects="$objects $o"
 done
@@ -65,7 +65,7 @@ $AR crD $mes_cpu-mes/libc.a $objects
 objects=
 for c in $libc_tcc_SOURCES; do
     echo "CC         $c"
-    $CC -c $CPPFLAGS $CFLAGS ${srcdest}$c
+    $CC -c $AM_CPPFLAGS $CPPFLAGS $AM_CFLAGS $CFLAGS ${srcdest}$c
     o=$(basename $c .c).o
     objects="$objects $o"
 done
@@ -79,7 +79,7 @@ CPPFLAGS="-D HAVE_CONFIG_H=1 -I ${srcdest}include -I ${srcdest}include/$mes_kern
 objects=
 for c in $mes_SOURCES; do
     echo "CC         $c"
-    $CC -c $CPPFLAGS $CFLAGS ${srcdest}$c
+    $CC -c $AM_CPPFLAGS $CPPFLAGS $AM_CFLAGS $CFLAGS ${srcdest}$c
     o=$(basename $c .c).o
     objects="$objects $o"
 done
diff --git a/build-aux/build.sh.in b/build-aux/build.sh.in
index 6ac111fa..ca7c46f7 100644
--- a/build-aux/build.sh.in
+++ b/build-aux/build.sh.in
@@ -48,14 +48,12 @@ if test -n "$GUILE" -a "$GUILE" != true; then
     ${SHELL} ${srcdest}build-aux/build-guile.sh
 fi
 
-debug=${debug--g}
-
-AM_CFLAGS="
--static
-$debug
-"
+AM_CFLAGS=
 
 if test $mes_libc = mes; then
+    AM_CFLAGS="
+-static
+"
     AM_CFLAGS="$AM_CFLAGS
 -nostdinc
 -nostdlib
@@ -71,7 +69,6 @@ AM_CPPFLAGS="
 "
 
 AM_LDFLAGS="
-$debug
 -L .
 "
 if test $mes_libc = mes; then
diff --git a/configure b/configure
index d48492d0..e6364c5e 100755
--- a/configure
+++ b/configure
@@ -252,23 +252,39 @@ MES_ARENA=100000000 exec ${SCHEME-guile} -L . --no-auto-compile -e '(configure)'
       (if result (set-field dependency (dependency-file-name) name)
           dependency))))
 
+(define (cflags-list)
+  (let ((cflags (getenv "CFLAGS")))
+    (if cflags (list cflags)
+        '())))
+
+(define (ldflags-list)
+  (let ((ldflags (getenv "LDFLAGS")))
+    (if ldflags (list ldflags)
+        '())))
+
 (define (check-preprocess-header-c cc header)
   (with-output-to-file ".config.c"
     (cut format #t "#include \"~a\"" header))
-  (with-error-to-file "/dev/null"
-    (cut zero? (system* cc "-E" "-o" ".config.E" ".config.c"))))
+  (let ((test (lambda _ (apply system* `(,cc "-E" "-o" ".config.E" ,@(cflags-list) ".config.c")))))
+    (zero? (if %verbose? (test)
+               (with-error-to-file "/dev/null"
+                 test)))))
 
 (define (check-compile-string-c cc string)
   (with-output-to-file ".config.c"
     (cut display string))
-  (with-error-to-file "/dev/null"
-    (cut zero? (system* cc "--std=gnu99" "-c" "-o" ".config.o" ".config.c"))))
+  (let ((test (lambda _ (apply system* `(,cc "--std=gnu99" "-c" "-o" ".config.o" ,@(cflags-list) ".config.c")))))
+    (zero? (if %verbose? (test)
+               (with-error-to-file "/dev/null"
+                 test)))))
 
 (define (check-link-string-c cc string)
   (with-output-to-file ".config.c"
     (cut display string))
-  (with-error-to-file "/dev/null"
-    (cut zero? (system* cc "--std=gnu99" "-o" ".config" ".config.c"))))
+  (let ((test (lambda _ (apply system* `(,cc "--std=gnu99" "-o" ".config" ,@(cflags-list) ,@(ldflags-list) ".config.c")))))
+    (zero? (if %verbose? (test)
+               (with-error-to-file "/dev/null"
+                 test)))))
 
 (define (parse-opts args)
   (let* ((option-spec
@@ -600,9 +616,9 @@ See \"Porting GNU Mes\" in the manual, or try --with-courage\n" mes-system)
                      ("@SCHEME@" . ,(if with-cheating? guile ""))
                      ("@SHELL@" . ,shell)
 
-                     ("@CFLAGS@" . ,(or (getenv "CFLAGS") ""))
+                     ("@CFLAGS@" . ,(or (getenv "CFLAGS") "-static -g"))
                      ("@CPPFLAGS@" . ,(or (getenv "CPPFLAGS") ""))
-                     ("@LDFLAGS@" . ,(or (getenv "LDFLAGS") ""))
+                     ("@LDFLAGS@" . ,(or (getenv "LDFLAGS") "-static -g"))
                      ("@HEX2FLAGS@" . ,(or (getenv "HEX2FLAGS") ""))
                      ("@M1FLAGS@" . ,(or (getenv "M1FLAGS") ""))