Post-push fix for broken build (-DWITH_ICU=system):
/sql/regexp/regexp_engine.h:103:70: error:
invalid conversion from const char16_t* to const UChar* {aka const short unsigned int*} [-fpermissive]
     m_re = uregex_open(upattern, length, flags, &error, &m_error_code);

Also: add valgrind suppressions for WITH_PROTOBUF:STRING=system

Change-Id: I775460b19adc4a6ae065c239fcf5664e9841cc38
Also: fix broken link of standalone unit tests