some more cosmetic fixes

doc/building.tex

@@ -16,7 +16,7 @@
 \begin{lstlisting}[language=bash]
 autoreconf --install       # only if ./configure does not exist yet
 ./configure [options] CXXFLAGS=-I<path> LDFLAGS=-L<path>
-make                       # library, and this manual and the doxygen pages if pdflatex/doxygen were found
+make                       # library, and this manual if pdflatex was found
 make check                 # builds the test programs, runs testoptimize
 make install
 \end{lstlisting}
@@ -117,5 +117,5 @@ This manual is in the subdirectory \header{doc}. \code{make manual} (alias \code
 is done only when a \code{.tex} file is newer than the PDF, and a \LaTeX{} error stops the build with the end of the log.
 A source code reference is generated by doxygen with the configuration file \header{doxygen.cfg} by \code{make doxygen}
 (output in \header{doxygen-doc}, rebuilt when a source file changes); it is independent of this manual.
-\code{make} (i.e.\ \code{make all}) builds both in addition to the library, each only if \code{configure} found
-\code{pdflatex} resp.\ \code{doxygen}; \code{make clean} removes \header{doc/.build} and \header{doxygen-doc} (not the PDF).
+\code{make} (i.e.\ \code{make all}) builds the manual in addition to the library if \code{configure} found
+\code{pdflatex}; the doxygen pages are built only by \code{make doxygen}. \code{make clean} removes \header{doc/.build} and \header{doxygen-doc} (not the PDF).