Hello,
I can't rebuild php 7.4.2 on current Slackware. Here is the error:

checking for IMAP support... yes
checking for IMAP Kerberos support... yes
checking for IMAP SSL support... /usr
checking for utf8_mime2text signature... new
checking for U8T_DECOMPOSE... yes
checking for pam_start in -lpam... no
checking for crypt in -lcrypt... yes
checking for krb5-gssapi krb5... yes
checking for openssl >= 1.0.1... yes
checking whether rfc822_output_address_list function present... no
checking whether build with IMAP works... no
configure: error: build test failed. Please check the config.log for details.

and here is the error from config.log

configure:40064: result: no
configure:40075: checking whether build with IMAP works
configure:40120: cc -o conftest -I/usr/include -O2 -fPIC -fvisibility=hidden -pthread -D_REENTRANT -L/usr/lib64 -Wl,-rpath,/usr/local/lib64/c-client/lib64 -L/usr/local/lib64/c-client/lib64 conftest.c -lc-client -lcrypt -lrt -lm -ldl -lpthread -lxml2 -lpcre2-8 -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err -lssl -lcrypto >&5
/usr/bin/ld: /usr/local/lib64/c-client/lib64/libc-client.a(osdep.o): in function `auth_oauth2_client':
(.text+0x345f): undefined reference to `mm_login_method'
/usr/bin/ld: (.text+0x3621): undefined reference to `mm_login_method'
collect2: error: ld returned 1 exit status
configure:40120: $? = 1
configure: program exited with status 1
configure: failed program was

try deleting the folder /usr/local/lib64/c-client and its contents and try the build again (probably libc-client.a has to be rebuilt too).

I try 3 times before write to forum. Did not work.

then I think you most probably don't have the latest version of the build script for php, because it has been patched for the thing you report on january 22nd

https://git.slackware.nl/current/com...87fec9d80a3fc6

just sync the Slackware current sources, delete (again) /usr/local/lib64/c-client and its content (the libc-client.a file), and try again.

Hm .. strange. Okay now is work. Thank you