Installation problem - mutex_lock/unlock or libpq.so ?

Installation of 7.4.2, even with just ./configure : gmake step ==>
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gmake[4]: Leaving directory
`/usr/home/smith/Temp_holding/staging-area/postgresql/postgresql-7.4.2/src/backend/parser'

gcc -O2 -fno-strict-aliasing -Wall -Wmissing-prototypes
-Wmissing-declarations pg_dump.o common.o pg_backup_archiver.o

pg_backup_db.o pg_backup_custom.o pg_backup_files.o pg_backup_null.o

pg_backup_tar.o dumputils.o ../../../src/backend/parser/keywords.o
-L../../../src/interfaces/libpq -lpq -L../../../src/port
-L/usr/local/openssl/lib -R/usr/local/pgsql/lib -lpam -lssl -lcrypto -lz
-lreadline -lcrypt -lcompat -lm -lutil -lpgport -o pg_dump

../../../src/interfaces/libpq/libpq.so: undefined reference to
`pthread_mutex_unlock'

../../../src/interfaces/libpq/libpq.so: undefined reference to
`pthread_mutex_lock'

gmake[3]: *** [pg_dump] Error 1

gmake[3]: Leaving directory
`/usr/home/smith/Temp_holding/staging-area/postgresql/postgresql-7.4.2/src/bin/pg_dump'

gmake[2]: *** [all] Error 2

gmake[2]: Leaving directory
`/usr/home/smith/Temp_holding/staging-area/postgresql/postgresql-7.4.2/src/bin'

gmake[1]: *** [all] Error 2

gmake[1]: Leaving directory
`/usr/home/smith/Temp_holding/staging-area/postgresql/postgresql-7.4.2/src'

gmake: *** [all] Error 2
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Help needed

Thanks

-- Adam --