When checksum_init is used in a program that does not also have a call to wiredtiger_open, there is an unresolved symbol:
libtool: link: cc -Wall -Wextra -Waddress -Waggregate-return -Wbad-function-cast -Wdeclaration-after-statement -Wformat-security -Wformat -Winline -Wmissing-declarations -Wmissing-field-initializers -Wnested-externs -Wpointer-arith -Wredundant-decls -Wshadow -Wunused -Wwrite-strings -Werror -g -Wall -o test_wt2695_checksum wt2695_checksum/main.o -L/Users/dda/wt/snappy/installed/snappy-1.1.1/lib -L/Users/dda/wt/ext/lz4/installed/lib /Users/dda/wt/git/process-init/test/utility/.libs/libtest_util.a ../../.libs/libwiredtiger.a -ldl -lpthread -lz -llz4 /Users/dda/wt/snappy/installed/snappy-1.1.1/lib/libsnappy.dylib Undefined symbols for architecture x86_64: "___wt_process", referenced from: _main in main.o ___wt_checksum_init in libwiredtiger.a(crc32-x86.o) ld: symbol(s) not found for architecture x86_64