doc/manual.txt: more tweaks.

doc/manual.txt

@@ -206,9 +206,9 @@ rather than additional binary package names.
  `subpackages`, set to `${XBPS_MASTERDIR}/destdir/${pkgname}-${version}`.
 
 *XBPS_BUILDDIR*::
- Directory to store the `source code` of the source package being processed.
- Usually this follows the `${pkgname}-${version}` naming. The `wrksrc`
- variable has the full path to the package source code directory.
+ Directory to store the `source code` of the source package being processed,
+set to `${XBPS_MASTERDIR}/destdir`. The package `wrksrc` is always stored
+in this directory.
 
 *XBPS_MACHINE*::
  The machine architecture as returned by `uname -m`.
@@ -308,7 +308,7 @@ built matching `uname -m` output. Example `only_for_archs="x86_64 armv6l"`
  This specifies the `build method` for a package. Read below to know more
 about the available package `build methods`. If `build_style` is not set,
 the package must define at least a `do_install()` function, and optionally
- more build phases as such `do_configure()`, `do_build()`, etc.
+more build phases as such `do_configure()`, `do_build()`, etc.
 
 *configure_script*::
  The name of the `configure` script to execute at the `configure` phase if
@@ -596,8 +596,8 @@ libfoo.so.1 foo-1.0_1
 - The second field specified the package name and minimal version required.
 - A third optional field specifies the architecture (rarely used).
 
-Creating users/groups at runtime
---------------------------------
+Creating system accounts/groups at runtime
+------------------------------------------
 
 There's a trigger along with some variables that are specifically to create
 **system users and groups** when the binary package is being configured.