algol68g fails to build on 10.6 i386: error: 'EXPORT_DYNAMIC_FLAGS' undeclared

[barracuda156]

mv -f ./src/a68g/.deps/a68g-plugin-basic.Tpo ./src/a68g/.deps/a68g-plugin-basic.Po
/opt/local/bin/gcc-mp-13 -DHAVE_CONFIG_H -I.  -I./src/include -D_DARWIN_C_SOURCE -DNCURSES_WIDECHAR -I/opt/local/include -I/opt/local/include -DBINDIR='"/opt/local/bin"' -DINCLUDEDIR='"/opt/local/include"' -pipe -Os -arch i386 -std=c17 -Wall -Wshadow -Wunused-variable -Wunused-parameter -Wno-long-long -I/opt/local/include -MT ./src/a68g/a68g-plugin-driver.o -MD -MP -MF ./src/a68g/.deps/a68g-plugin-driver.Tpo -c -o ./src/a68g/a68g-plugin-driver.o `test -f './src/a68g/plugin-driver.c' || echo './'`./src/a68g/plugin-driver.c
In file included from ./src/include/a68g.h:99,
                 from ./src/a68g/plugin-driver.c:26:
./src/a68g/plugin-driver.c: In function 'plugin_driver_compile':
./src/a68g/plugin-driver.c:87:73: error: 'EXPORT_DYNAMIC_FLAGS' undeclared (first use in this function)
   87 |       ASSERT (a68_bufprt (cmd, SNPRINTF_SIZE, "ld %s -o \"%s\" \"%s\"", EXPORT_DYNAMIC_FLAGS, FILE_PLUGIN_NAME (&A68_JOB), FILE_BINARY_NAME (&A68_JOB)) >= 0);
      |                                                                         ^~~~~~~~~~~~~~~~~~~~
./src/include/a68g-defines.h:160:9: note: in definition of macro 'ASSERT'
  160 |   if (!(f)) {\
      |         ^
./src/a68g/plugin-driver.c:87:73: note: each undeclared identifier is reported only once for each function it appears in
   87 |       ASSERT (a68_bufprt (cmd, SNPRINTF_SIZE, "ld %s -o \"%s\" \"%s\"", EXPORT_DYNAMIC_FLAGS, FILE_PLUGIN_NAME (&A68_JOB), FILE_BINARY_NAME (&A68_JOB)) >= 0);
      |                                                                         ^~~~~~~~~~~~~~~~~~~~
./src/include/a68g-defines.h:160:9: note: in definition of macro 'ASSERT'
  160 |   if (!(f)) {\
      |         ^
make[1]: *** [src/a68g/a68g-plugin-driver.o] Error 1
make[1]: *** Waiting for unfinished jobs....