Source/LexerParser: Suppress "Use of zero-allocated memory" warning

clang scan-build warns about YY_CURRENT_BUFFER_LVALUE being zero-
allocated, but the whole point of the macro is to know that it's
not zero. Wrap the entire file in an "#ifndef __clang_analyzer__"
block in order to suppress the warning.
20 jobs for clang-scan-build-warnings
Status Job ID Name Coverage
  External
passed cdash

passed cmake-dash3win7-windows-release-ninja

00:24:33

passed cmake-hythloth-linux-debug-makefiles+sphinx

passed cmake-hythloth-linux-release-lint-iwyu-tidy

passed cmake-moonshade-osx-debug-ninja

00:10:19

passed cmake-moonshade-osx-release-makefiles

00:12:25

passed cmake-terfin-windows-release-vs2017

passed ghostflow-check-master

passed ghostflow-stager

passed cmake-hythloth-linux-debug-makefiles+sphinx

00:53:00

passed cmake-hythloth-linux-release-lint-iwyu-tidy

00:02:54

passed cmake-terfin-windows-release-vs2017

00:45:28

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager