diff --git a/ext/wasm/GNUmakefile b/ext/wasm/GNUmakefile
index fa46c9633a..143ee8b9f1 100644
--- a/ext/wasm/GNUmakefile
+++ b/ext/wasm/GNUmakefile
@@ -59,6 +59,13 @@ emcc.bin ?= $(word 1,$(wildcard $(EMSDK_HOME)/upstream/emscripten/emcc) $(shell
 ifeq (,$(emcc.bin))
   $(error Cannot find emcc.)
 endif
+emcc.version := $(shell "$(emcc.bin)" --version | sed -n 1p \
+                  | sed -e 's/^.* \([3-9][^ ]*\) .*$$/\1/;')
+ifeq (,$(emcc.version))
+  $(warning Cannot determine emcc version. This might unduly impact build flags.)
+else
+  $(info using emcc version [$(emcc.version)])
+endif
 
 wasm-strip ?= $(shell which wasm-strip 2>/dev/null)
 ifeq (,$(filter clean,$(MAKECMDGOALS)))
@@ -501,7 +508,6 @@ emcc.cflags :=
 emcc.cflags += -std=c99 -fPIC
 # -------------^^^^^^^^ we need c99 for $(sqlite3-wasm.c).
 emcc.cflags += -I. -I$(dir.top)
-
 ########################################################################
 # emcc flags specific to building .js/.wasm files...
 emcc.jsflags := -fPIC
@@ -509,7 +515,6 @@ emcc.jsflags += --minify 0
 emcc.jsflags += --no-entry
 emcc.jsflags += -sWASM_BIGINT=$(emcc.WASM_BIGINT)
 emcc.jsflags += -sMODULARIZE
-emcc.jsflags += -sSTRICT_JS
 emcc.jsflags += -sDYNAMIC_EXECUTION=0
 emcc.jsflags += -sNO_POLYFILL
 emcc.jsflags += -sEXPORTED_FUNCTIONS=@$(EXPORTED_FUNCTIONS.api)
@@ -519,6 +524,13 @@ emcc.exportedRuntimeMethods := \
 emcc.jsflags += $(emcc.exportedRuntimeMethods)
 emcc.jsflags += -sUSE_CLOSURE_COMPILER=0
 emcc.jsflags += -sIMPORTED_MEMORY
+ifeq (3.1.31,$(emcc.version))
+  emcc.jsflags += -sSTRICT_JS=0
+  $(warning Disabling -sSTRICT_JS for emcc $(emcc.version): \
+     https://github.com/emscripten-core/emscripten/issues/18610)
+else
+  emcc.jsflags += -sSTRICT_JS=1
+endif
 emcc.environment := -sENVIRONMENT=web,worker
 ########################################################################
 # -sINITIAL_MEMORY: How much memory we need to start with is governed
diff --git a/manifest b/manifest
index fc03db56d3..fd21e7b6dc 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Work\saround\supstream\semscripten\s3.1.31\sbug\s[https://github.com/emscripten-core/emscripten/issues/18609].
-D 2023-01-27T05:14:34.038
+C Extract\semcc\sversion\sin\sJS\sbuild\sand\suse\sit\sto\sconditionally\sset\sbuild\sflags.\sInitially\sa\sworkaround\sfor\s[https://github.com/emscripten-core/emscripten/issues/18610|Emscripten\sticket\s#18610]\sbut\smay\shave\sother\suses.
+D 2023-01-27T17:14:55.199
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -466,7 +466,7 @@ F ext/userauth/sqlite3userauth.h 7f3ea8c4686db8e40b0a0e7a8e0b00fac13aa7a3
 F ext/userauth/user-auth.txt e6641021a9210364665fe625d067617d03f27b04
 F ext/userauth/userauth.c 7f00cded7dcaa5d47f54539b290a43d2e59f4b1eb5f447545fa865f002fc80cb
 F ext/wasm/EXPORTED_FUNCTIONS.fiddle.in 27450c8b8c70875a260aca55435ec927068b34cef801a96205adb81bdcefc65c
-F ext/wasm/GNUmakefile e1bd4abe13929dbc4fd9da06d189c61d28fc7a539b2cab942f6300172539d8a5
+F ext/wasm/GNUmakefile 31cf62436f306eed8c8aa66991653395f62e52af7ad21a0de02f7d780cb8c398
 F ext/wasm/README-dist.txt dab111337028af58ec11cb35c2e1a82398217c399c7499fefab0509a0499a5d7
 F ext/wasm/README.md ef39861aa21632fdbca0bdd469f78f0096f6449a720f3f39642594af503030e9
 F ext/wasm/api/EXPORTED_FUNCTIONS.sqlite3-api d6a5078f48a5301ed17b9a30331075d9b2506e1360c1f0dee0c7816c10acd9ab
@@ -2044,8 +2044,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P b7b896fb448a7f46eb88eadadb1359255aec637a384cabcdd526276a02f4f0b4
-R 652518ccc6e34aeabd9f5e7c9c0f903b
+P fa784101775b795077a23c211b5b16f51ad5a13967c284511f310dfcbfa9f77a
+R 3675add13eb3ce53caed9c7b4b0b8fb4
 U stephan
-Z 9f5aabec0ec6e83053759380211a0e0c
+Z e36df8532ba6c8eb3243e966cb4c4025
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 1ff4d9398a..df7e52ee6d 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-fa784101775b795077a23c211b5b16f51ad5a13967c284511f310dfcbfa9f77a
\ No newline at end of file
+3773934e91c20ca2433cc414aaba75de9a4a4318fd1126fb781dba510ddefd94
\ No newline at end of file