diff --git a/math/eukleides/Makefile b/math/eukleides/Makefile
index 059920262427..1f120ab5d02b 100644
--- a/math/eukleides/Makefile
+++ b/math/eukleides/Makefile
@@ -3,7 +3,7 @@
 
 PORTNAME=	eukleides
 PORTVERSION=	1.5.4
-PORTREVISION=	5
+PORTREVISION=	6
 CATEGORIES=	math
 MASTER_SITES=	http://www.eukleides.org/files/
 
@@ -16,10 +16,13 @@ LICENSE_FILE=	${WRKSRC}/COPYING
 RUN_DEPENDS=	pstoedit:graphics/pstoedit \
 		getopt>=0:misc/getopt
 
-USE_TEX=	latex
 USES=		bison gettext iconv gmake readline:port tar:bzip2
+USE_TEX=	latex
 INSTALL_TARGET=	install PREFIX=${STAGEDIR}${PREFIX}
 
+# Fix build with clang11
+CFLAGS+=	-fcommon
+
 PORTDOCS=	de.pdf fr.pdf
 PORTEXAMPLES=	greenwich.euk sundial.euk vonkoch.euk
 
@@ -38,7 +41,8 @@ post-patch:
 		 -e "s|%%PREFIX%%|${PREFIX}|g" \
 		 -e "s|%%LOCALBASE%%|${LOCALBASE}|g" \
 		 -e "s|%%EXAMPLESDIR%%|\$${PREFIX}/${EXAMPLESDIR_REL}|g" \
-		 -e "s|%%DOCSDIR%%|\$${PREFIX}/${DOCSDIR_REL}|g"
+		 -e "s|%%DOCSDIR%%|\$${PREFIX}/${DOCSDIR_REL}|g" \
+		 -e "s|%%CFLAGS%%|${CFLAGS}|g"
 	@${GREP} -lFR "gcc" ${WRKSRC} |${XARGS} ${REINPLACE_CMD} \
 		-e "s|gcc|${CC}|g"
 
diff --git a/math/eukleides/files/patch-bash_euktoeps b/math/eukleides/files/patch-bash_euktoeps
index a18cda179805..2cbbd8f2e4b1 100644
--- a/math/eukleides/files/patch-bash_euktoeps
+++ b/math/eukleides/files/patch-bash_euktoeps
@@ -1,6 +1,6 @@
---- bash/euktoeps.orig
+--- bash/euktoeps.orig	2010-04-27 06:31:00 UTC
 +++ bash/euktoeps
-@@ -31,7 +31,7 @@
+@@ -31,7 +31,7 @@ USAGE
  exit $1
  }
  
diff --git a/math/eukleides/files/patch-build_Makefile b/math/eukleides/files/patch-build_Makefile
index dd19dc4cba04..8ac065dc09fb 100644
--- a/math/eukleides/files/patch-build_Makefile
+++ b/math/eukleides/files/patch-build_Makefile
@@ -1,6 +1,6 @@
---- build/Makefile.orig
+--- build/Makefile.orig	2010-04-27 06:31:00 UTC
 +++ build/Makefile
-@@ -12,12 +12,12 @@
+@@ -12,12 +12,12 @@ LFLAGS = -8
  YACC = bison
  YFLAGS = -d
  CC = gcc
@@ -9,8 +9,9 @@
  ifneq ($(strip $(LOCALES)),)
  MOFLAGS = -DMO_DIR=\"$(MO_DIR)\" 
  endif
- CFLAGS = -Wall -D__$(BINARY)__ $(IFLAGS) $(MOFLAGS)
+-CFLAGS = -Wall -D__$(BINARY)__ $(IFLAGS) $(MOFLAGS)
 -LDFLAGS = -lncurses -lreadline -lm
++CFLAGS = -Wall -D__$(BINARY)__ $(IFLAGS) $(MOFLAGS) %%CFLAGS%%
 +LDFLAGS = -lncurses -lreadline -lm "-L%%LOCALBASE%%/lib" -lintl
  VPATH = $(COMMON_DIR):$(MAIN_DIR):$(BUILD_DIR)
  
diff --git a/math/eukleides/files/patch-doc_eukleides.texi b/math/eukleides/files/patch-doc_eukleides.texi
index 438d96bca9d4..225d9b134486 100644
--- a/math/eukleides/files/patch-doc_eukleides.texi
+++ b/math/eukleides/files/patch-doc_eukleides.texi
@@ -1,4 +1,4 @@
---- doc/eukleides.texi.orig
+--- doc/eukleides.texi.orig	2010-04-27 06:31:00 UTC
 +++ doc/eukleides.texi
 @@ -6,12 +6,14 @@
  
diff --git a/math/eukleides/files/patch-man_Makefile b/math/eukleides/files/patch-man_Makefile
index 71610706c0bd..24750479f2ba 100644
--- a/math/eukleides/files/patch-man_Makefile
+++ b/math/eukleides/files/patch-man_Makefile
@@ -1,6 +1,6 @@
---- man/Makefile.orig
+--- man/Makefile.orig	2010-04-27 06:31:00 UTC
 +++ man/Makefile
-@@ -3,13 +3,10 @@
+@@ -3,12 +3,9 @@
  
  include ../Config
  
@@ -8,10 +8,9 @@
 +MAN_PAGES := $(wildcard *.1)
  
  man: $(MAN_PAGES)
- 
+-
 -%.1.gz: %.1
 -	@gzip -c $< > $@
--
+ 
  install: $(MAN_PAGES)
  	@install -d $(MAN_DIR)
- 	@install -m 0644 $^ $(MAN_DIR)