build: fix a typo in configure.ac that had deactivated most warnings.

configure.ac

@@ -215,7 +215,7 @@ LOL_TRY_CXXFLAGS(-Wparentheses, [AM_CPPFLAGS="${AM_CPPFLAGS} -Wparentheses"])
 LOL_TRY_CXXFLAGS(-Wreorder, [AM_CXXFLAGS="${AM_CXXFLAGS} -Wreorder"])
 
 dnl  Disable these warnings because they're annoyingly verbose
-LOL_TRY_CXXFLAGS(-Wno-psabi, [AM_CPPFLAGS="${AM_CXXFLAGS} -Wno-psabi"])
+LOL_TRY_CXXFLAGS(-Wno-psabi, [AM_CPPFLAGS="${AM_CPPFLAGS} -Wno-psabi"])
 
 
 AC_CHECK_LIB(m, sin, MATH_LIBS="${MATH_LIBS} -lm")