diff --git a/devel/doxygen/files/patch-src_CMakeLists.txt b/devel/doxygen/files/patch-src_CMakeLists.txt
index e21a2adf3ef4..ffb57903cde8 100644
--- a/devel/doxygen/files/patch-src_CMakeLists.txt
+++ b/devel/doxygen/files/patch-src_CMakeLists.txt
@@ -1,5 +1,5 @@
---- src/CMakeLists.txt.orig	2020-12-24 14:02:11 UTC
-+++ src/CMakeLists.txt
+--- src/CMakeLists.txt.orig	2020-12-24 23:02:11.000000000 +0900
++++ src/CMakeLists.txt	2021-07-13 18:08:11.910412000 +0900
 @@ -2,7 +2,6 @@
  
  include_directories(
@@ -8,7 +8,16 @@
      ${PROJECT_SOURCE_DIR}/liblodepng
      ${PROJECT_SOURCE_DIR}/libmscgen
      ${PROJECT_SOURCE_DIR}/libversion
-@@ -345,7 +344,7 @@ target_link_libraries(doxygen PRIVATE
+@@ -68,7 +67,7 @@
+ 
+ # ce_parse.h
+ add_custom_command(
+-    COMMAND ${BISON_EXECUTABLE} -l -d -p ce_parsexpYY ${CMAKE_CURRENT_LIST_DIR}/constexp.y -o ce_parse.c
++    COMMAND ${BISON_EXECUTABLE} -l -d ${CMAKE_CURRENT_LIST_DIR}/constexp.y -o ce_parse.c
+     DEPENDS ${CMAKE_CURRENT_LIST_DIR}/constexp.y
+     OUTPUT ${GENERATED_SRC}/ce_parse.h
+     WORKING_DIRECTORY ${GENERATED_SRC}
+@@ -345,7 +344,7 @@
      doxymain
      doxycfg
      qtools
diff --git a/devel/doxygen/files/patch-src_constexp.y b/devel/doxygen/files/patch-src_constexp.y
new file mode 100644
index 000000000000..a80bccf19338
--- /dev/null
+++ b/devel/doxygen/files/patch-src_constexp.y
@@ -0,0 +1,11 @@
+--- src/constexp.y.orig	2021-07-13 18:16:30.107422000 +0900
++++ src/constexp.y	2021-07-13 18:16:34.345420000 +0900
+@@ -35,7 +35,7 @@
+ 
+ %}
+ 
+-%name-prefix "constexpYY"
++%define api.prefix {constexpYY}
+ %define api.pure full
+ %lex-param {yyscan_t yyscanner}
+ %parse-param {yyscan_t yyscanner}