needs to link with -llapack

The linker complains about undefined references:

eigensrc/eigx.o: In function `eigx_':
eigx.c:(.text+0x14b): undefined reference to `dspev_'
eigensrc/eigx.o: In function `eigxv_':
eigx.c:(.text+0x220): undefined reference to `dspev_'
eigensrc/eigx.o: In function `cdc_':
eigx.c:(.text+0x29b): undefined reference to `dpotrf_'
eigensrc/eigx.o: In function `inverse_':
eigx.c:(.text+0x396): undefined reference to `dgetrf_'
eigx.c:(.text+0x3f7): undefined reference to `dgetri_'
eigensrc/eigx.o: In function `solve_':
eigx.c:(.text+0x4d7): undefined reference to `dgetrf_'
eigx.c:(.text+0x536): undefined reference to `dgetrs_'
eigensrc/eigx.o: In function `geneigsolve_':
eigx.c:(.text+0x602): undefined reference to `dsygv_'
collect2: error: ld returned 1 exit status
<builtin>: recipe for target 'eigensrc/pcatoy' failed
make: *** [eigensrc/pcatoy] Error 1
eigx.o: In function `eigx_':
eigx.c:(.text+0x14b): undefined reference to `dspev_'
eigx.o: In function `eigxv_':
eigx.c:(.text+0x220): undefined reference to `dspev_'
eigx.o: In function `cdc_':
eigx.c:(.text+0x29b): undefined reference to `dpotrf_'
eigx.o: In function `inverse_':
eigx.c:(.text+0x396): undefined reference to `dgetrf_'
eigx.c:(.text+0x3f7): undefined reference to `dgetri_'
eigx.o: In function `solve_':
eigx.c:(.text+0x4d7): undefined reference to `dgetrf_'
eigx.c:(.text+0x536): undefined reference to `dgetrs_'
eigx.o: In function `geneigsolve_':
eigx.c:(.text+0x602): undefined reference to `dsygv_'
collect2: error: ld returned 1 exit status
<builtin>: recipe for target 'pca' failed
make: *** [pca] Error 1

These references come from the lapack library. By adding -llapack the linker flags this error disappears and all references are found. This is required especially when the available OpenBLAS was built without LAPACK and a separate LAPACK library is used.

Review the build rules for the pca and eigensrc/pcatoy targets, and inspect eigensrc/eigx.c to understand which LAPACK symbols are referenced. Reproduce the linker failure, then verify that both targets build successfully when the separate LAPACK library is available and linked.