Fix LIBNAMESUFFIX handling in CMake and update documentation

- Fix cmake/system.cmake: LIBPREFIX was incorrectly overwritten when
  LIBNAMESUFFIX was defined, losing both "lib" prefix and "openblas"
- Fix Makefile.rule docs: typo used LIBNAMESUFFIX instead of LIBNAMEPREFIX
- Fix Makefile.rule docs: removed misleading underscores from examples
- Fix docs/build_system.md: removed incorrect claim about automatic
  underscore separator

The implementation does not add an underscore before the suffix - users
who want a separator should include it in their LIBNAMESUFFIX value
(e.g., LIBNAMESUFFIX=_omp).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: vtjnash

Makefile.rule

@@ -5,15 +5,15 @@
 # This library's version
 VERSION = 0.3.30.dev
 
-# If you set this prefix, the library name will be lib$(LIBNAMESUFFIX)openblas.a
-# and lib$(LIBNAMESUFFIX)openblas.so, with a matching soname in the shared library
-# 
+# If you set this prefix, the library name will be lib$(LIBNAMEPREFIX)openblas.a
+# and lib$(LIBNAMEPREFIX)openblas.so, with a matching soname in the shared library
+#
 # LIBNAMEPREFIX = scipy
 
-# If you set the suffix, the library name will be libopenblas_$(LIBNAMESUFFIX).a
-# and libopenblas_$(LIBNAMESUFFIX).so. Meanwhile, the soname in shared library
-# is libopenblas_$(LIBNAMESUFFIX).so.0.
-# LIBNAMESUFFIX = omp
+# If you set the suffix, the library name will be libopenblas$(LIBNAMESUFFIX).a
+# and libopenblas$(LIBNAMESUFFIX).so. Meanwhile, the soname in shared library
+# is libopenblas$(LIBNAMESUFFIX).so.0.
+# LIBNAMESUFFIX = _omp
 
 # You can specify the target architecture, otherwise it's
 # automatically detected.

cmake/system.cmake

@@ -638,8 +638,8 @@ endif()
 
 set(LIBPREFIX "lib${LIBNAMEPREFIX}openblas")
 
-if (DEFINED LIBNAMESUFFIX)
-  set(LIBPREFIX "${LIBNAMEPREFIX}_${LIBNAMESUFFIX}")
+if (DEFINED LIBNAMESUFFIX AND NOT "${LIBNAMESUFFIX}" STREQUAL "")
+  set(LIBPREFIX "lib${LIBNAMEPREFIX}openblas${LIBNAMESUFFIX}")
 endif ()
 
 if (NOT DEFINED SYMBOLPREFIX)

docs/build_system.md

@@ -143,9 +143,8 @@ ensures that there are a sufficient number of buffer sets available.
   no symbolic linking to variant names (default is `0`)
 - `LIBNAMEPREFIX`: prefix that, if given, will be inserted in the library name
   before `openblas` (e.g., `xxx` will result in `libxxxopenblas.so`)
-- `LIBNAMESUFFIX`: suffix that, if given, will be inserted in the library name
-  after `openblas`, separated by an underscore (e.g., `yyy` will result in
-  `libopenblas_yyy.so`)
+- `LIBNAMESUFFIX`: suffix that, if given, will be appended to the library name
+  after `openblas` (e.g., `_yyy` will result in `libopenblas_yyy.so`)
 - `SYMBOLPREFIX`: prefix that, if given, will be added to all symbol names
   *and* to the library name
 - `SYMBOLSUFFIX`: suffix that, if given, will be added to all symbol names