diff --git a/srcpkgs/giac/patches/fix-configure.patch b/srcpkgs/giac/patches/fix-configure.patch
new file mode 100644
index 00000000000000..b3c964b40a6590
--- /dev/null
+++ b/srcpkgs/giac/patches/fix-configure.patch
@@ -0,0 +1,12 @@
+--- a/configure.ac
++++ b/configure.ac
+@@ -524,8 +524,8 @@
+ 	      AC_SUBST(FLTK_LIBS)
+               cd src && ln -sf ../fltk-1.3.8 && cd ..
+            fi
+-        fi
+             ])
++        fi
+ LIBS="$save_LIBS"
+ 
+ AC_CHECK_HEADERS(dfu_lib.h) 
diff --git a/srcpkgs/giac/template b/srcpkgs/giac/template
index cec87f557bc61c..ddf780a63b764e 100644
--- a/srcpkgs/giac/template
+++ b/srcpkgs/giac/template
@@ -1,6 +1,6 @@
 # Template file for 'giac'
 pkgname=giac
-version=2.0.0.18
+version=2.0.0.21
 revision=1
 build_style=gnu-configure
 configure_args="--disable-micropy --disable-quickjs"
@@ -15,7 +15,7 @@ license="GPL-3.0-or-later"
 homepage="https://www-fourier.univ-grenoble-alpes.fr/~parisse/giac.html"
 changelog="https://www-fourier.univ-grenoble-alpes.fr/~parisse/install_en#new"
 distfiles="https://www-fourier.univ-grenoble-alpes.fr/~parisse/debian/dists/stable/main/source/giac_${version%.*}-${version##*.}.tar.gz"
-checksum=25e2a3d9686c9a6800d9e6b4a243eeeb0af7602067f060e6aab4138e63e417db
+checksum=3e7fa1c281a21ab74ed66ef247faffe5a105bc11be1f7715f31b4368ce8dcbc8
 
 # need more than 4*65536 stack, see try_parse() in gen.cc line 11812
 LDFLAGS="-Wl,-z,stack-size=2097152"
@@ -35,14 +35,6 @@ case "$XBPS_TARGET_MACHINE" in
 	*) ;;
 esac
 
-post_extract() {
-	# Missing... triggers doc rebuild which fails
-	touch doc/en/tutoriel.stamp
-	# remove a binary that works only for a particular host
-	# the binary will be rebuilt using host compiler
-	rm -f src/mkjs
-}
-
 pre_configure() {
 	# use full version in banner -- upstream hides last component
 	vsed -i configure.ac \