Envinject fails to set variables mainly with uppercase letters and potential special meaning (at least the first time). See the envinject-test config which is attached.

Following messages will be output from envinject plugin:

...
[EnvInject] - Injecting as environment variables the properties content
'baseoutDir=/var/lib/jenkins/workspace/envinject test/dbg_trc
compileOutput=--baseoutdir="${baseoutDir}"
CONSFLAGS=${compileOutput}
ONSFLAGS=${compileOutput}
NSFLAGS=${compileOutput}
SFLAGS=${compileOutput}
FLAGS=${compileOutput}
LAGS=${compileOutput}
AGS=${compileOutput}
GS=${compileOutput}
SCONSFLAGS=${compileOutput}
SCONSFLAG=${compileOutput}
SCONSFLA=${compileOutput}
SCONSFL=${compileOutput}
SCONSF=${compileOutput}
SCONS=${compileOutput}
SCON=${compileOutput}
SCO=${compileOutput}
SC=${compileOutput}
S=${compileOutput}
flags=${compileOutput}'

[EnvInject] - Unset unresolved 'SFLAGS' variable.
[EnvInject] - Unset unresolved 'SCONSFLAGS' variable.
[EnvInject] - Unset unresolved 'FLAGS' variable.
[EnvInject] - Unset unresolved 'SCONS' variable.
[EnvInject] - Injecting as environment variables the properties content
'SCONSFLAGS=--baseoutdir="/var/lib/jenkins/workspace/envinject test/dbg_trc"'

[envinject test] $ /bin/sh -xe /tmp/hudson2448047751840058372.sh

...}}