diff --git a/devel/root/Makefile b/devel/root/Makefile
index 9d3b5d1a5ca4..b9e7ccbef2e4 100644
--- a/devel/root/Makefile
+++ b/devel/root/Makefile
@@ -1,85 +1,96 @@
 PORTNAME=	root
 DISTVERSION=	6.28.02
 CATEGORIES=	devel science math parallel python
 MASTER_SITES=	https://root.cern/download/
 DISTFILES=	${PORTNAME}_v${DISTVERSION}.source${EXTRACT_SUFX}
 
 MAINTAINER=	erik@tenku.dk
 COMMENT=	Data analysis framework made at CERN
 WWW=		https://root.cern/
 
 LICENSE=	LGPL21
 LICENSE_FILE=	${WRKSRC}/LGPL2_1.txt
 
 BUILD_DEPENDS=	${PYNUMPY} \
 		bash:shells/bash \
 		nlohmann-json>=3:devel/nlohmann-json
 LIB_DEPENDS=	libAfterImage.so:graphics/libafterimage \
 		libcfitsio.so:astro/cfitsio \
 		libcurl.so:ftp/curl \
 		libfftw3.so:math/fftw3 \
 		libfreetype.so:print/freetype2 \
 		libftgl.so:graphics/ftgl \
 		libgif.so:graphics/giflib \
 		libgl2ps.so:print/gl2ps \
 		libgsl.so:math/gsl \
 		liblz4.so:archivers/liblz4 \
 		libpcre.so:devel/pcre \
 		libpng.so:graphics/png \
 		libtbb.so:devel/onetbb \
 		libtiff.so:graphics/tiff \
 		libvdt.so:math/vdt \
 		libxkbcommon.so:x11/libxkbcommon \
 		libXrdCl.so:databases/xrootd \
 		libxxhash.so:devel/xxhash \
 		libzstd.so:archivers/zstd
 
 USES=		blaslapack:openblas cmake compiler:c++17-lang desktop-file-utils \
 		gettext-runtime gl gnome iconv jpeg mysql:57 pgsql:13.0+ python:3.9+ \
 		shebangfix sqlite ssl xorg
 USE_GL=		glew glu opengl
 USE_GNOME=	cairo gdkpixbuf2 glib20 librsvg2 libxml2
 USE_XORG=	ice sm x11 xau xaw xcb xcomposite xcursor xdamage xdmcp xext \
 		xfixes xfont xfont2 xft xi xinerama xkbfile xmu xpm xrandr \
 		xrender xres xscrnsaver xt xv xxf86vm
 
 SHEBANG_FILES=	config/rootssh etc/dictpch/makepch.py etc/proof/utils/circle.sh \
 		etc/proof/utils/crypt etc/proof/utils/pps \
 		etc/proof/utils/proofctl.sh etc/proof/utils/proofinstall.sh
 
 CMAKE_ARGS=	-DCMAKE_CXX_STANDARD=17
 CMAKE_ON=	gnuinstall soversion
 CMAKE_OFF=	builtin_gtest
 
 CONFIGURE_WRKSRC?=	${WRKDIR}/.build
 MAKE_ENV+=		ROOTSYS=${CONFIGURE_WRKSRC}
 
 OPTIONS_DEFINE=	DOCS ROOT7
 OPTIONS_DEFAULT=	ROOT7
 OPTIONS_SUB=	yes
 
 ROOT7_DESC=	Enable supplementary preview features of ROOT version 7
 ROOT7_CMAKE_BOOL=	root7
 
 .include <bsd.port.options.mk>
 
 PLIST_SUB+=	SHLIB_SHVER="${DISTVERSION:R}" \
 		SHLIB_VER="${DISTVERSION}"
 
 # Some .modulemap, .pcm and .idx files are not installed on aarch64, a few .pcm files are exclusive to aarch64 and files LIBRARY.pcm are renamed libLIBRARY_rdict.pcm on aarch64
 .if ${ARCH} == "aarch64"
 PLIST_SUB+=	NOT_INSTALLED_ON_AARCH64="@comment " ONLY_INSTALLED_ON_AARCH64="" AARCH64_PCM_PREFIX="lib" AARCH64_PCM_SUFFIX="_rdict"
 .else
 PLIST_SUB+=	NOT_INSTALLED_ON_AARCH64="" ONLY_INSTALLED_ON_AARCH64="@comment " AARCH64_PCM_PREFIX="" AARCH64_PCM_SUFFIX=""
 .endif
 
 # Some files only installed with LLVM/Clang 13 (used on FreeBSD 12.4 and 13.x)
 # TODO: Introduce USES+=llvm:min=14 instead when this can be deemed not too obtrusive on supported releases
 #       -- the post-patch step further down can then be phased out as well
-.if 1204000 <= ${OSVERSION} && ${OSVERSION} < 1400000 && ${OSVERSION} != 1301507
+.if 1204000 <= ${OSVERSION} && ${OSVERSION} < 1302000 && ${OSVERSION} != 1301507
 PLIST_SUB+=	ONLY_INSTALLED_WITH_LLVM_CLANG_13=""
 .else
 PLIST_SUB+=	ONLY_INSTALLED_WITH_LLVM_CLANG_13="@comment "
 .endif
 
-.include <bsd.port.mk>
+.include <bsd.port.pre.mk>
+
+# In LLVM/Clang 10.0.1 (used on FreeBSD 12.3), the cstdalign header is missing from the std modulemap, but it is declared included in ROOT's std modulemap - this has to be removed.
+# See https://github.com/llvm/llvm-project/blob/main/libcxx/include/module.modulemap.in#L181
+# The same seems to be the case for the other headers defined in the variable "modules" below.
+.if ${OSVERSION} < 1204000
+modules=	cstdalign cuchar experimental/string_view ext/functional ext/numeric ext/type_traits.h bits_alloc_traits_h bits/allocator.h bits/basic_ios.h bits/cpp_type_traits.h bits/exception_defines.h bits/ios_base.h bits/locale_facets.h bits_stl_algobase_h bits_stl_iterator_h bits/stl_iterator_base_types.h bits/stl_map.h bits/stl_pair.h bits_stl_tree_h bits/uniform_int_dist.h
+post-patch:
+	SCRIPTDIR=${SCRIPTDIR} MODULEMAP=${WRKSRC}/interpreter/cling/include/cling/std.modulemap ${SH} ${SCRIPTDIR}/remove-modules-from-modulemap.sh "${modules}"
+.endif
+
+.include <bsd.port.post.mk>
diff --git a/devel/root/scripts/remove-modules-from-modulemap.awk b/devel/root/scripts/remove-modules-from-modulemap.awk
new file mode 100755
index 000000000000..adabed818d2f
--- /dev/null
+++ b/devel/root/scripts/remove-modules-from-modulemap.awk
@@ -0,0 +1,9 @@
+BEGIN {
+  exclude = exclude; #trim left and right
+  gsub(/[[:blank:]]/, "|", exclude);
+  gsub(/\//, "\\/", exclude);
+  ex_regx = "module[[:blank:]]+\"(" exclude ")\".*{[[:blank:]]*$";
+}
+
+$0 ~ ex_regx, $0 ~ /^[[:blank:]]*}[[:blank:]]*$/  { next ; }
+{print}
diff --git a/devel/root/scripts/remove-modules-from-modulemap.sh b/devel/root/scripts/remove-modules-from-modulemap.sh
index 64df1b9c2ba0..c118c7637bf0 100755
--- a/devel/root/scripts/remove-modules-from-modulemap.sh
+++ b/devel/root/scripts/remove-modules-from-modulemap.sh
@@ -1,27 +1,7 @@
 #!/bin/sh
 
 # Script removes module definition blocks in LLVM/Clang .modulemap
-# files in-place in the file path stored in the variable MODULEMAP
+# files "in-place" in the file path stored in the variable MODULEMAP
 
-sp='[[:space:]]'
-
-mdls="" ; i=0
-for m in "$@" ; do
-  i=$((i+1))
-  mdls="$mdls($m)"
-  [ $i -ne $# ] && mdls="$mdls|"
-done
-
-script="\
-/^$sp*(explicit)?$sp*module$sp*\"$mdls\"$sp*\{$sp*\$/ {
-  :l
-    N
-    s/}/}/
-    tx
-    bl
-  :x
-    d
-}\
-"
-
-sed -i '' -E "$script" "$MODULEMAP"
+modules=$1
+tmp=${MODULEMAP}.tmp && awk -f ${SCRIPTDIR}/remove-modules-from-modulemap.awk -v exclude="${modules}" ${MODULEMAP} > ${tmp} && mv ${tmp} ${MODULEMAP} || rm ${tmp}