I've got it... I needed to disable all the AVX stuff.

Presumably, this is broken because I cross-compile.
Also, this is where I'm rewriting history to remove
the debug libs that were over 100M

src/syncterm/GNUmakefile

@@ -36,18 +36,16 @@ else
 endif
 
 ifdef win
- ifeq (${os}, "win32")
-  CFLAGS += -I${3RDP_ROOT}/win32.release/libjxl/include -DJXL_THREADS_STATIC_DEFINE -DJXL_STATIC_DEFINE
-  LDFLAGS += -L${3RDP_ROOT}/${os}.release/libjxl/lib -static-libstdc++ -static-libgcc
-  EXTRA_LIBS += -ljxl
-  EXTRA_LIBS += -ljxl_threads
-  EXTRA_LIBS += -lbrotlidec
-  EXTRA_LIBS += -lbrotlicommon
-  EXTRA_LIBS += -lhwy
-  CFLAGS += -DWITH_JPEG_XL -DWITH_STATIC_JXL
-  CFLAGS += -DWITH_JPEG_XL_THREADS
-  OBJS += $(MTOBJODIR)$(DIRSEP)libjxl$(OFILE)
- endif
+ CFLAGS += -I${3RDP_ROOT}/win32.release/libjxl/include -DJXL_THREADS_STATIC_DEFINE -DJXL_STATIC_DEFINE
+ LDFLAGS += -L${3RDP_ROOT}/${os}.release/libjxl/lib -static-libstdc++ -static-libgcc
+ EXTRA_LIBS += -ljxl
+ EXTRA_LIBS += -ljxl_threads
+ EXTRA_LIBS += -lbrotlidec
+ EXTRA_LIBS += -lbrotlicommon
+ EXTRA_LIBS += -lhwy
+ CFLAGS += -DWITH_JPEG_XL -DWITH_STATIC_JXL
+ CFLAGS += -DWITH_JPEG_XL_THREADS
+ OBJS += $(MTOBJODIR)$(DIRSEP)libjxl$(OFILE)
 else
  ifeq ($(shell pkg-config libjxl --exists && echo YES), YES)
   CFLAGS += $(shell pkg-config libjxl --cflags)