sci-libs/cgcode: Port to EAPI 8

Closes: https://bugs.gentoo.org/688888
Signed-off-by: Jakov Smolić <jsmolic@gentoo.org>

sci-libs/cgcode/cgcode-1.0-r2.ebuild

@@ -1,33 +1,35 @@
 # Copyright 1999-2021 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
-EAPI=5
+EAPI=8
 
-inherit epatch fortran-2 flag-o-matic toolchain-funcs
+inherit fortran-2 flag-o-matic toolchain-funcs
 
 DESCRIPTION="Conjugate gradient Codes for large sparse linear systems"
 HOMEPAGE="http://fetk.org/codes/cgcode/index.html"
 SRC_URI="http://www.fetk.org/codes/download/${P}.tar.gz"
-
-SLOT="0"
-KEYWORDS="amd64 x86 ~amd64-linux ~x86-linux"
-LICENSE="GPL-2"
-IUSE=""
-
-RDEPEND="virtual/blas"
-DEPEND="${RDEPEND}
-	virtual/pkgconfig"
-
 S="${WORKDIR}"/${PN}
 
+LICENSE="GPL-2"
+SLOT="0"
+KEYWORDS="amd64 x86 ~amd64-linux ~x86-linux"
+
+RDEPEND="virtual/blas"
+DEPEND="${RDEPEND}"
+BDEPEND="virtual/pkgconfig"
+
+PATCHES=(
+	"${FILESDIR}"/${PV}-gentoo.patch
+)
+
 src_prepare() {
-	epatch "${FILESDIR}"/${PV}-gentoo.patch
+	default
 
 	# GCC 10 workaround
 	# bug #722000
 	append-fflags $(test-flags-FC -fallow-argument-mismatch)
 
-	cat >> make.inc <<- EOF
+	cat >> make.inc <<- EOF || die
 	F77 = $(tc-getFC)
 	FFLAGS = ${FFLAGS}
 	BLASLIBS = $($(tc-getPKG_CONFIG) --libs blas)

sci-libs/cgcode/files/1.0-gentoo.patch

@@ -1,5 +1,3 @@
-diff --git a/makefile b/makefile
-index 4813b55..f20af02 100644
 --- a/makefile
 +++ b/makefile
 @@ -1,21 +1,23 @@
@@ -33,8 +31,6 @@ index 4813b55..f20af02 100644
  	
  clean :
  	rm -f *.o goos good
-diff --git a/src/makefile b/src/makefile
-index 10cf6c3..1dfd02d 100644
 --- a/src/makefile
 +++ b/src/makefile
 @@ -1,16 +1,17 @@
@@ -60,8 +56,6 @@ index 10cf6c3..1dfd02d 100644
  	
  clean :
  	rm -f *.o $(THISLIB)
-diff --git a/util/makefile b/util/makefile
-index 6dad0d1..5c9d24f 100644
 --- a/util/makefile
 +++ b/util/makefile
 @@ -6,11 +6,12 @@ SOBJLIB = saxpy.o scopy.o sdot.o snrm2.o sscal.o